a quality competitive BSP build, will run you 15 grand easily. and for real, a BSP car when complete is pretty much undrivable on the street. id reconsider that class.
but in order of BSP legal things to change on a car that make the most difference to the least difference:
-as big of R-comps mounted on as wide of wheels as possible
- something like 3 degrees negative camber all the way around (probably more in front than in back), maybe a slight amount of toe out in back to promote rotation
-as stiff of springs and roll bars as you can muster with some decently valved adjustable dampers (lowest quality: koni yellows)
-tune for e85 and as much boost as possible
-cat delete, full 3 inch exhuast
AWD controller to push more power rear might help too, im not terribly familiar with if the haldex on the mk6 is any good at that or not.
The car isn't mine, it's already built, and I'm driving it for a local shop. It currently makes 370 whp (3" exhaust, HPFP, tune, custom shop intake) and has custom valved shocks (for race/competition) with 650f/450r spring rates.
My math, based on corner weights and a motion ration of 0.98 front and 1 in the rear, says that I should be running 550f/450r, but I'm not too concerned because I think I can balance things with tires/wheels and bar. What spring rates would you suggest?
Which leads to - what's the beastiest rear bar available? Largest I've seen in 27mm.
Wheels/tires - what's the widest wheel/largest tire I can fit on here? I know some Mk 6 GTI folks are running 285/30/18 Hoosiers.
Can I run a 17" wheel on the R and clear the brakes?
E85 - the car owner SWEARS that the turbo is maxed out on 93. He's very close with APR and says that's what they told him. That's why he says they won't run E85. That doesn't make much sense - E85 basically dumps pure oxygen in there which will make more power, even without more boost, plus it should allow more timing. Is there a reason people are afraid of E85?
I like the idea of toe out rear but I'm planning to hold it as a last resort. Plan is to go -3 front, -2 rear, see what happens. I usually put a tick of toe out front - is there any reason to avoid that in these cars?
Anything else you can helpfully provide to me?