Finally completed the build on my 2008.5 Speed 3.
First step was Bell CAI in summer of '08.
February of this year I added a Hypertech Max Energy Sport with CAI update. Seemed to run stronger, bit BOV popping above 5200rpm. Replaced stock BOV with a forge v2 with blue spring and 2 shims--worked great.
In late spring I added a Street Unit TMIC and Vibrant downpipe back exhaust. Car misfired like crazy at higher rpms. I thought it was spark plug blow-out, so I installed 1-step colder NGK Iridium IX's and tightened the gap to .022. Misfire persisted. Hypertech folks assured me their tune "adapts" to these mods and should work fine.
Took my car to the good folks at 5252 Motorsports in Victoria. On the dyno the car was running way rich and actually GAINED power removing the Hypertech and returning to stock tune--I was at about 210 on the DynoDynamics, which tends to read quite a bit lower than DynoJet. A stock Speed 3 on 5252 Motorsport's dyno pulled 194hp.
I flogged the Hypertech on eBay and got a Cobb AccessPort. As I did not have an after-market downpipe, I stayed with Stage 1 tune with 93 octane. Big bump to 258 hp and 303 tq (blue lines on dyno graph at bottom of link below).
I then had a Corksport downpipe installed and went to Stage 2 with Turboback exhaust, CAI and Upgraded TMIC. Power is now 282.8 with 315.9 tq (red lines on dyno graph). The BIG gain is the +55 Ft Lb of tq at 2500rpm with this downpipe (over 70 Ft Lb at 2400!!). Turbo spools up way quicker. These gains down low are way better than I've seen with plots for the Cobb DP.
See story and dyno plot:
http://5252motorsports.blogspot.com/...ean-mazda.html
Suspension mods are Mazdaspeed Springs with camber plates, Hotchkis sway bars, Koni Yellows and Enkei PF01's (6 pounds lighter than stock per wheel). StreetUnit billet rear engine mount and TWM short shifter with bushings keeps the drivetrain from moving around and reduced wheel hop and torque steer.