Originally Posted by
Reasoned1
3.46 is what I was thinking since the car is for thrills not long hauls.
I would love to hear more about your upgrade. I'm in central Vermont, so not alot of BMW shops around, but I have a great garage I go to and they're all for attempting the swap. Shouldn't be a big deal, right? Pull the old one off the axles and drive shaft and slap the new one in, right? Please tell me it's that easy... My 2004 xi has 3.46 (among a few other things), and it feels punchier lower down but, of course, it peters out higher up whereas the ZHP just keeps building.
Just noticed you're in Arlington, VA--my son lives in Arlington, and he facilitated the purchase of my ZHP at Avazi Auto Group in Gaithersburg, MD.
Yes it is that easy. I can do it in two hours start to finish laying on my garage floor. There are a few tricks to it but any good mechanic will be able to figure it out. I would have the mechanic check the rear differential bushing while they are in there. The rubber has a habit of splitting/cracking. Sometimes you can see it without removing the diff if it's bad enough but sometimes you can only see/test it with the diff out like we did with Daniel's car.
If your car is for thrills, then definitely go for the 3.46. There are only two performance upgrades that give you a real performance increase without going into the engine internals: Differential gearing change and forced induction.
Daniel gives good advise about getting a donor diff. I think that may be your best bet in your situation. You can always sell your original diff if you don't want it laying aound.
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