Thanks for the write up! The verdict is in, I just tried it out and the changes that I've experienced are that each gear adds about 5mph, which made 4th gear reach 70 now with the throttle pinned, but 5th gear had become even weaker

now 5th gear maintains the speed and ever so slowly decelerates to 60. Still, better in every way except 5th, but I was expecting as much.