Yeh bit of a difference between the GT and ST though the ST's to my knowledge are getting pretty rare.I have heard ages ago that about 40-50 were brought over but ive only ever seen 2 apart from mine. As for warming up the engine a bit,I thought the 2TB had twin carbs? I have a webber with manifold that you can pm me about which will help a little but to be honest your flogging a dead horse by trying to get too much performance out of it.My suggestion would be to pull the 2t out but keep it aside for a nice clean and drop in a 2tg,the rest of the unique features are mainly in the interior so do what you can to restore them to factory specs.I will track down the number of an original interior restorer for you that I have lying around somewhere.