e30 318is 1990

[retroboy]

this is my current car, ihave restored much of it but the engine has a lot of milage (133,000) so i was thinking of replacing it with either a 2ltr or 2.5ltr six cylinder , also i much prefare smoothness of the sixcylinder!! can anyone tell me how difficult this will be and do i need different prop shafts or diff ? any feedback would be greatly appreciated

[dark_sounds]

yes, new diff, nto sure on prop shaft but yes to gear box.
dont bother with 2.0 go for 2.5, or tbh save yourself the hassle and keep the IS engine and just look after it

your call :0