Honestly....
With the std rb25 plenum the RB30 really does have issues reving hard.
Throw an aftermarket plenum on it with a set of mild cams and they easily make their peak power up around 8000rpm.
The plenum and correctly matched turbo is the key.
The benefit of the RB30 is its awesome rod to stroke ratio. Its considered a perfect rod/stroke ratio for track use. If you don't believe me do a little research in to why and you will see.
The RB30 spools a GT35r .82 all up by ~3500rpm with a nice plenum and mild cams they hold power well through to 8k. Thats a 4500rpm power band thats making at least 200rwkw by 4000rpm, thats pretty damn impressive.
Its all about average power and on the track a 'correctly' setup RB30 WILL be easier and quicker to drive around the track.
Leave the std rb25 plenum on them and they feel like a great big diesel and don't rev much past 6k, great for the street but not so great for the track or high terminal speeds at the 1/4.
Don't be worried the rb30 will rev slow due to its longer stroke...
Don't tell me this rev's slow.
RB30DET, stock bottom end, td06-20g 240rwkw 10psi. Ran a 12.19 1/4.
All the theory is just that.. Theory. In practice there's no replacement for displacement in this case.