You can just as easily loose your licence doing the speed limit (dangerous driving charge for accelerating unnecessarily quickly) as going over, so I wouldn't worry so much about that As other have said, take both for a drive (if you can): anything other than your own impressions are rather pointless.
FWIW, you can get an RB26 going lower in the rev range without too much work: cams, exhaust and intake mods, and wise turbo choice will help considerably.
LW.