You could get an ERST engine and then retro fit the EFI bits from a FRST. You'd need the inlet manifold and injectors, the loom and a 36 - 1 toothed wheel for the crankshaft senosr to read (or a FRST flywheel) and all the sensors, coilpack etc. With a bit of luck you could get your FRST spec engine with a T3 tubo for not too much money, plus you could sell all the bits you didn't need.

With regards to the fitting of it all as they're both the same block and head I don't think that would be a problem.

Mazakman