I'm not a regular poster here but you guys seem to like your DIY tuning. Mine is maybe not quite so DIY as your attempts, really only the throttle body and intake were genuinely DIY, but everything else was bought by myself.
My car is a UK 2000 model S. That means no cats in the manifolds/headers, so only 2 cats in the exhaust system.
I did various bolt on bits and dyno'd each time, same place, same operator etc etc.
1) Standard
2) Ebay silencer and manifolds, K&N panel (same as Topspeed by the pictures)
3) 74mm throttle body, custom 83mm intake from MAF to TB
4) Custom remap
All the usual maintenance was done in between: oil changes, new plugs, air filter clean etc etc.
I have one more dyno run to do back on the original dyno but doing the maths it's a 25bhp peak increase at the wheels with gains starting from 3-3.5k rpm all the way through to the limiter. These are dyno proven gains so you can see the effects of each of the stages.
Top line you are looking at circa +9bhp, +6bhp and lastly +13bhp (dyno flywheel estimate as I can't remeber the at wheels figures, but the increase is broadly the same).
The rest of the pics and write ups you can read on the UK based boxa.net forum
http://www.boxa.net/forum/index.php?showtopic=53075
Porsche Boxster S
Porsche Boxster
Threaded Mode
