my dad put on old sigma engine in (the 2.4 astron motor) our 4wd express. They are damn tough. The standard 2 litre engine is a gutless piece of shit. But your mate should put the sigma turbo engine in.
The guy that owns Hills Motorsports has put an lancer evo motor into his 4wd starwagon. Supposedly the standard gbox can handle it and it can pull mad 4wd burnouts