GHawz13,
From what I've read on other posts on the same subject, the concensus is to go with 275/50/15s on stock rims (to fill up the wheel well without rubbing). The side walls do bulge out a little on 15x7 rims (I've seen it on a buddy's TR). Ideally you want to get 15x8 or larger like 15x8.5 or 15x9 rims in order to eliminate the bulge. But some guys don't mind the bulge.
I purchased a pair of BFG Comp T/A Drag Radials for better traction b/c I don't drive my TR in the rain anyways. Other TR owners who have tried both have said BFGs were better for dry traction than Nittos but Nittos were better for rain and, being a harder tire, did not wear as quickly as BFGs. I think Nittos are priced slightly higher than BFGs but not by much.
So I guess it just depends on what you do with your car...drive in nice weather only or both.
HTH,