My Conclusion: r33 gts-t 0.5bar (spikes 2 0.7bar) exhuast (catback), airfilter, bov
I ran 1st: Shell Unleaded - car ran ok, pinging like fu**k after 4000rpm got about 200km 2 1/2 a tank
2nd: Shell optimax - still pinging (but not as much), power was the same ran abit over 200km 2 1/2 a tank (around 210, 220)
3rd (and currently) Bp ultimate - no pinging, power much better, responds better and wouldnt die out as much at top rpm, kms 2 a tank abit unknowed as i have been driving it hard for along time and getting anywhere from 200 to 230km 2 1/2 a tank
my conclusions: BP is the best; pinging doesnt happen which results is a smoother power
an example: I would shift before 5000rpm when giving the car some shit when not running BP as the ping would result in a big power lost (car would feel like there was no turbo)
now car runs all the way to limited (7200rpm) and lost of power isn't that noticable at top rpm, car runs lovly in 1st,2nd and 3rd gear till limited (full power no lost)
after that 4th and 5th gear lose alittle bit of power at high rpm cuz of my custum turbo