You shouldnt have gear whine as long as they are installed right. I think when they are not correctly shimmed (sp), they can make a lot of noise. I have 3.73's in mine with no whine. Get a good shop to do them and you should have no problems.
I had it installed already and it was a bad one. So a grove was worn in my gears. He sid it woould whine now but qouldnt cause any further problems. Just want to know how audible it will be