No matter which rearend...with the power you say your motor will be making, make sure you beef up the differential support. The BDR TD cars come with something already, and there are aftermarket kits for it.
Here is one...
http://www.aatuning.com/viewproduct.aspx?id=Product42
I have run into three separate folks here in SoCal that have had this issue, where the support bolt snaps. For the record, all of them had the larger bolt in there differentials.
As for Gearing...I would not recommend going higher than 3.46. Great gear for quick burst and for highway driving.