My ring and pinion broke

So now I need a new ring and pinion....I have a 97 Z28 A4 that originally came with a 3.23 in it and I had put a 4.10...but I'm stepping down this time to a 3.73 and I can't remember if the housing is 7.5 or 8.5? So if somebody could tell me what I need to get and where to get the cheapest price since it is the Christmas season I would appreciate it greatly....thanks Jason

Should probably be in the drivetrain section but anyway. The rears are all 7.5" 10-bolts. I got my gears and installation kit from http://www.Thunderracing.com. I'm assuming you don't need a carrier but I found mine on ebay with 500 miles on it for $200. Good luck. Nathan