^Keep in mind there is no reason to rev beyond what your turbo can support. And if you're after good street spool you dont want a turbo that gets going at 6000rpms. I think a 35R size (65lb/min) turbo should spool around the 4500-5000rpm mark and still hold power nicely to 8500+rpm. If you want 9000-10000rpms power potential you may want to consider a 40R size turbo but that will negativly effect your "good street spool." Obviously a lot of this is dependent on what headwork you have and cams you're using.