I've added an Iceman intake and a DC Sport 4:2:1 header and I'm not sure if going to an overbore TB will add significantly to performance. Inlinefour does overbores of existing TB's, but since they can only add 4mm to mine and I'd be without my car for a couple of weeks even using expedited shipping to CA and back I don't find that an attractive option. I'd be interested in specific TB recommendations as well as information as to the precise bore diameter of the stock TB and of the opening into the intake manifold. Also, how precisely does the TB need to martch the diameter of the opening into the intake manifold.