***Disclaimer - Any replica parts I'll be speaking about below are ones that I've had personal experience with from the USA, and not products from any other sponsor on this forum - the comments below do not reflect any of the sponsor's products, they are purely from my own hands on experience with U.S. replica body kit manufacturers***
I'm getting a lot of questions now about body kit paint & installation, and I'm finding many of you don't know much about them, which can cause some frustration down the road. Hopefully this will give you some background knowledge and help you decide what part type and material is best for you.
The first step involved when you are ready to purchase a body kit is to choose what style you'd prefer. This is all up to personal taste and preference, so I can't really go into detail with that.
After you decide what style you'd want on your car, the second most important factor is what material the kit is made from. There are five main materials aftermarket manufacturers use when they make any body kits - Fiberglass, FRP / PFRP, Urethane, ABS plastic, and Carbon Fiber.
Next you have to choose whether or not you want to buy a replica part, or an authentic part.
Once you have all the above sorted out, you've gotta grab some quotes from body shops and look around to see who will do the best work.
What material / process body kits are made from, and the advantages and disadvantages of those materials (from an autobody point of view):
Fiberglass
Pure fiberglass parts are very rigid and tough to modify (if modifications are needed for proper fitment) and often when they are damaged they are usually beyond repair (because if they are hit hard enough they just break in half), or it is often cheaper to buy a new part rather than repair the existing part. That being said, fiberglass parts from high end manufacturers usually pay a lot of attention to their fitment and moulding process, so usually they are very straight and have good lines. Also, fiberglass is very porous so primer and paint can adhere to it really well, and fiberglass is fairly lightweight.
FRP / PFRP
Fiber Reinforced Plastic (FRP), or Pliable Fiber Reinforced Plastic (PFRP) basically means a fiber interweave is laced into a plastic moulded part, to give the part or panel strength while maintaining flexibility. PFRP is a little more flexible and can bend a bit more than FRP. I'd probably say 80-90% of higher end German and Japanese (JDM) body kits are made from PFRP now. They are fairly easy to repair if they become damaged, and primer / paint usually adheres well to these types of parts. They are also fairly light (not as light as fiberglass or carbon fiber) but they are more durable than fiberglass or CF.
Urethane / Injection Moulded Polyurethane
Urethane parts have the most flexibility on the market. They are very durable, and very easy to repair. Most replica manufacturer's have polyurethane versions of their parts because they have become very popular in recent years, due to their high durability. They are relatively easy to modify to fit properly on the vehicle, but if they are poorly moulded in the first place they cannot be fixed or changed - polyurethane parts are AS IS. If they are really bad fitment it's not like we can add a few sheets of fiberglass and resin to fill in some gaps, once urethane is moulded that's what the fitment will be. They are easy to bend and shape a little bit to make them fit the lines of the vehicle, but if they are moulded too short or very poorly there's no way around it. Urethane parts are probably the heaviest parts around - so if weight is a consideration I'd lean more towards fiberglass, carbon fiber, or FRP / PFRP. Also, all polyurethane parts require adhesion promoter to be applied to the surface prior to prime and paint, because they are (most of the time) injection moulded, which means they are very smooth and don't have a lot of pores to which the primer and paint have to grab on to. This means the cost to paint urethane parts is more expensive (if you want it done correctly), but not by a considerable amount. Some very cheap urethane parts that I've dealt with have had a chemical reaction to the primer and paint, which caused an uneven finish and bubbling - remember, you get what you pay for!!!
ABS Plastic
I don't see too many ABS body kits out there, the only one I've seen in person was for a 2009 GTi. Basically they are purely plastic parts, very durable, flexible, and easy to repair. Adhesion promotor is also needed with these parts for prime and paint. Read the urethane section above, it's pretty much the same as far as fitment goes, but ABS plastic parts are a little more rigid than urethane parts. They can bend and flex a LOT, but they will crack if put under enough stress.
Carbon Fiber
Carbon fiber parts have the same qualities that fiberglass parts do. They are very rigid, and 95% of the time if they are damaged they cannot be repaired. The main reason why most people want carbon fiber parts is because they look great, and also because they are extremely lightweight. Usually people who buy carbon fiber parts don't want to paint over them (to show off that they have CF!) but it's possible to paint them. If the carbon fiber part is authentic and good quality, it will have a gel coating on top of it (which is not clear coat) which must be removed prior to paint - we've done it many times with no problems. Be very careful when purchasing carbon fiber - sometimes manufacturers claim their parts are real carbon fiber interweave, but in reality they are fiberglass parts with either a coating or type of vinyl that is placed on top to make it look like carbon fiber.
Again, do your research and buy from reputable sources!!!
Replica vs Authentic parts
***Disclaimer - Any replica parts I'll be speaking about below are ones that I've had personal experience with from the USA, and not products from any other sponsor on this forum - the comments below do not reflect any of the sponsor's products, they are purely from my own hands on experience with U.S. replica body kit manufacturers***
The majority of replica parts that I've had to deal with were a complete pain in the ass to paint and install, to be blunt . They don't fit right, some of them have a chemical reaction to paint, are hard to modify, cost more in the end to install vs authentic parts, and in the end my customers aren't happy. Be very careful and do your research before you spend thousands of dollars on body kit panels & parts. Just because a company claims they are the best in the industry doesn't make it so - there's one specific aftermarket replica dealer I had business with in the past which clearly stated on their website: "We are known throughout the industry for our superb fitment and quality". Yet every single part that came my way from them was absolutely horrible, both with fitment and quality. (After the first one came in I gave them a chance and ordered a few more, after I saw what they thought quality was I terminated my account.)
The main problem with most replicas (not all, there are good and bad ones definitely) is that they cost MUCH more to paint and install vs authentic body kit parts. For example, I recently completed a Tiburon full replica lip kit for a customer right before Christmas (it was an Xmas present). I tried to convince the customer to purchase authentic JDM parts (which weren't that much more expensive in this case), but they chose to purchase the cheaper replicas. The replica kit was roughly $1500, and I had to charge close to $2200 for installation and paint because of the poor fitment and quality. We had to fabricate about 18 custom brackets just to make the parts line up correctly. Now I'm sure they could have taken the parts to another body shop and got a cheaper install / paint price, but they wanted it done correctly, and we have a lifetime guarantee on our work. A high quality authentic lip kit will cost more, but labour would be less than $1000 to paint and install (for the authentic version of this specific kit). Ultimately it's up to you to decide... spend more on parts and have much better quality and fitment (and some authentic aftermarket parts will actually raise the value of your vehicle, like Nismo, Brabus, or AC Schnitzer products) and spend less on labour, or buy the cheapest parts possible and spend much, much more on labour to paint and make them fit properly.
All I have to say about getting a body kit installed correctly is found here: http://www.my350z.com/forum/the-loun...0z-ruined.html -> enough said about that topic.
I'm not gonna say that it always works out to the same price (whether you buy replicas or authentic). Authentic parts will cost more, but the fitment and quality far exceed any replica part that you may find from the US or Ebay, and installation / painting costs will be drastically lower.
Here's an example - the parts below are side skirts for a 2004 Golf GTi. One is a replica from a US company, and one is an authentic Oettinger side skirt from Germany. I'll let you figure out which is which
Notice how the authentic part is straight as an arrow, and actually has a groove to slide the skirt into place? Where the aftermarket part is wavy & simply relies on two sided tape for fitment and to attach itself to the vehicle. It's those little differences that make a huge impact on labour costs.
Choosing a body shop to paint and install your body kit
Almost everyone I speak to thinks that installing an OEM part is the exact same as installing an aftermarket body kit part, and they can bring their body kit to any body shop to paint & install it. In reality the process is VERY different. When choosing a body shop to install or paint your body kit ask them if they have any extensive aftermarket modification experience. If they are simply an auto collision repair facility with no aftermarket or customs experience, you don't want to go there. Doesn't matter how experienced their techs are, if they haven't worked with custom body kits before they know next to nothing about installing them properly.
Price shouldn't always be your main consideration (see the 350z link above). Quality, customs experience, and a warranty should always be the first things you should look at when getting quotes. Ask for a portfolio or samples of their aftermarket customs work! If they don't have anything, move on. I'm sure everyone can agree, you don't want to pay twice for paint or installation when you're already spending thousands to modify your vehicle - so make absolutely sure the body shop you go to is extremely qualified, won't cause damage to your vehicle, has aftermarket customs experience, will install your parts correctly to ensure safety, and has a guarantee on their work!
The bottom line is, whether buying authentic panels or replicas, you definitely get what you pay for. A $40 lip will get you $40 quality and fitment in the end.