I went from 3.15 to 3.73 in my car and I’m very pleased with it. Car should have came with 3.73’s if you ask me. It helped my car down low where it struggled with the 3.15’s.
I know this is an older thread, but I just put a set of 3.73’s in my 10r80 car. I have had no issues whatsoever. I haven’t changed anything in computer yet and speedometer is still correct according to gps. I went from 3.15’s to 3.73’s. I’m running ET street r’s and they seem to do pretty decent...