I wish motorsport would make a 3.90 ratio so I could do that and not worry about it being noisy. I dont trust motive or richmond
What tire do you plan on running?
That makes a huge effect on this IMO.
If I was running a shorter tire, I would likely do the 3.73, but my goal is to run a 10 on the DR I will be driving on.
I'd personally risk the 3.90 as long as there was some reassurance/warranty that if its noisy it would be replaced.
-J