Hi,
First post, new to VW and looking for some advice

. I have a MK4 with a poorly (read dead) AXP engine. Now it appears these are few and far between so my question is this...
If I were to change from an AXP to another 1.4 (or 1.6 even) engine of a different code is there much work involved? ECU, Gearbox? Breathers, Sensors?
Are any other codes a relatively close fit? Looking around the BCA engine appears to be the closest match.
Any information (large or small) would be greatly appreciated...