i hear this is a good bang for your buck mod for rev ups but what about 5at's? also what is the difference between each besides the price?

 

Doesn't matter if you have a 5AT or 6MT, I went from a 3.5 to a 3.7 and its definitely noticeable. The higher the number the shorter the gears (quicker acceleration). However, going with that high of a ratio may mess with the car's systems. So far I have not had any problems but I didn't change the ratio too much. Your speedometer will read faster then your actual speed as well.

 

+1, speedometer will be off but this also happens with aftermarket rims that are different sizes. Would def be a good mod for autos, what is the price range?

 

yeah sounds good but everywhere i look online it says it wont fit an auto only manual

 

about 600 for 3.9 about 8-900 for 4.0

 

It depends:
My current diff came off a G37s sedan and required no fabrication. Some will have an extended pinion shaft and 3-bolt flange but its not hard to make these work on any G35.
These threads have the info required:

https://g35driver.com/forums/drivetr...tial-swap.html
https://g35driver.com/forums/drivetr...-into-5at.html

True, but its more like 10mph off with this mod

 

Is there a way to correct that with the car's electronics?

 

how much will these shorter diffs actually shave off of quarter mile times?