Someone with a GT35R..opinions.

[Shane@DBPerformance]

They mostly spoolup quicker between gears, once it is already spinning quick. You don't have to shift quite as fast to keep it in boost when you are racing. Otherwise, they don't do much else. They don't make more power and they don't really initially spoolup all that much quicker. So it isn't worth it to most people who woudl rather spend the extra money on some other part. If you can afford it, go for it.