hate to tell you but I watched Mike Gay destroy everyone all summer long last year with a Centro outside on track that was low bite and sandy. M3 Holeshots front and rear type of track.
It is 100% driver preference. When he got his B5 a few months ago and had to run it here, he was significantly slower than he was with his Centro. As soon as he got his B5M, he was significantly faster than the Centro. And this was on a medium grip surface that is dominated by Rear Motor cars.
Like I said.... it's driver.