doesn't matter what you drive(6 vs 8), unless you track it often. Last time I checked the speed limit hasn't changed(much). Car design FTW. And if you think smaller powerplants can't put out, take a spin in a GTR...
Curious, how many tuners get asked, "is it a modded 4 or a 6 banger?"
maybe the OP is going through the 'shoulda bought a V8' saga:(