In that case, go with the Fiesta bottom end, head and inlet manifold, sell off the rest of the bits you dont need from the Fiesta to boost funds (ECU etc), buy a Gotech off Jamie (which I'm pretty sure you can fit yourself) and you can then run coilpack etc with a fully mappable system.

Of course you could also just go with the MFi plan, add a Group A cossie coil and cross your fingers every time you flick the switch for the gas Kind of like the current Cosworth tuning you are experimenting with

I would say go with the stock T3 though, I ran one for ages and it was awesome. The only reason I swapped it was becasue we were switching to a very special roller bearing unit, otherwise I would have kept it.
Traction was pretty good, although we did have a play around with a few bits and pieces on the front suspension to help