> you could however mate a 2.5V v6 to the cally driver train
or even the Omega C30XE 3L V6 engine into the Calibra but use Calibra air induction and igntion system for it all to fit under the bonnet. Then you have F28 and 4x4 system too. Already done though by an ex Cournteay show car.
Not sure what you mean by that but in your oringal post you say Calibra 2L 16v 4x4. Remeber this 4x4 is different to the Calibra Turbo C20LET 4x4 system, this is much stronger. The 2L 16v 4x4 had (I belive) a F20 gearbox but with TX bolted onto it. So you can still use a F28 in there, but the 4x4 is weaker, and putting a bigger engine in there, you may see problems with relibilty issues with the weaker 4x4 system.
> The 4x4 mechanism is the same on everybody the Calibra I have seen. Only the gear is different!
Looking through EPC it mentioned 4x4 parts on the F20 gearbox side of things for the Calibra. The main 4x4 items do seem to be the gear ratios inside. Plus looking at the rear box, it dosn't show a c20let 4x4 and a c20xe 4x4 version, so they must use the same GM p/n and hecne same parts. I was just told that the c20xe 4x4 is not a strong as the c20let 4x4 system.