you will realise this when doing 100ks at lower revs and you try to put your foot down up a hill it just wont happen. cheers andy
doesn't happen anyway
SCC is right: it's definitely a bit harder on the motor and gearbox getting off the mark and accelerating at speed. But if you're doing a lot of highway driving, there's much to recommend a change in diff ratio. And/or a look at tyre profile. It would amaze you the difference in rolling circumference between a standard 6.40 x 13 cross ply and a 70 series radial.
cheers
RET