Dane

Hello all.
I have a uk spec MY97 turbo wagon and my big end has just decided to give up, so was along the lines of rebuilding the engine, but has been suggested to me that i get a new complete 2.5 sti short block which comes with uprated fuel pump,front or top mount intercooler, exhaust headers, uppipe, gasket set and fitting kit instead. And it says that you can use the existing heads and all other parts of the old engine.
My question is has anybody done a conversion like this and have they had a bad experiences from it or is it as easy as it says?
The wagon is completely standard at the moment, except for exhaust. Would i also be able to keep the standard gearbox and ecu if running the 2.5?
Regards
Dane