My 2 Door with boost will maintain 90 with no problems...not that its a good idea. 70 was a non issue with 37 KM2s and 4.88s. Like Dalearyous said, its probably good advice to go with what feels right. Maybe drive someone else's vehicle with the gearing desired to see if it has the right feel? Might take some time but still, you could potentially avoid a mistake.