All of the below mods made very very slight improvements IMO. Combined, however, they made a
very nice car to drive. When I removed them (before sending the car back), there was a definite lack of oomph and zing when I drove the car.
In no particular order...
Lighter Wheels - Immediate difference felt in braking. I'm sure acceleration would benefit too, however it was difficult to tell at the time.
Increased offset - Front and rear track was widened by 14mm in total. That was combined with...
Eibach sportlines - Together with the wider track, tyre wear was SPOT ON despite trackdays/hard cornering. Understeer was reduced slightly and the car felt very neutral. The car felt very stable on bumps. Sideways FTW.
Braided Hoses + DS2500 + Superdot 4 fluid - Once hot (very hot), the DS2500s are absolutely superb! Rears didn't last long though - can't think why. Gut-wrenching braking when combined with....
Strut brace (front) - People may argue that they're useless, however under braking I felt that it really stabilised the front. The car tracked beautifully IMO.
Gearbox mount bushings - they caused the most horrendous vibrations whilst idling, however the drivetrain felt a bit sharper.
Green Cotton Filter - I doubt it increased peak power, however it sharpened things up as far as acceleration was concerned - it felt as if the air was always available as soon as I hit the throttle.
Decat - I believe there was an improvement at the very top end of the rev range. A lovely zippy/zingy sound too.
I can't remember anything else I did, but if I do I'll update the post.
Oms.