Actually it all depends. If it is an ATX, I wouldn't bother swaping any engine. If it is an I4, FS-03, then your only option would be an FS-ZE, but as far as I know no MX6/Probe have been able to swap one succesfully. However if it is a V6 then there are more options, an KL-ZE which is 200bhp, a KF-ZE which is same as the US KL-03, in terms of horsepower. ECU is NOT a problem, except maybe the FS-ZE, never dealt with one. But with anything else just slap on a Megasquirt and off you go. To swap from I4 to V6, is not really worth it, because it involves swaping master cylinders, and rear hubs.