To the OP, I think a twin turbo 302 would be awesome, I have toyed with the idea of dropping a FI 302 in a Supra. Make sure you don't hack the car to hell to make shit fit, and be creative. As for oil pressure and water temp, utilize the 7M sending units and you can use the factory gauges. Get a tach signal modifier to get your tach working as well, then you are set. Also, make sure you build with the appropriate engine parts, no need to go through engines like toilet paper.
Good luck.
I Have seen a 302 in a Supra before, it was FI and had the AOD electronically controlled transmission too. Guy really liked the combo.