Im just wondering, how easy/difficult is it to change a std ED motor to an XR ED motor and whats involved?

The head is the diference cluding cam and compression.. With 300 kpa fuel reg and EEC... Fit wise they are both the same...

head, cam, fuel pressure regualator and the pritty red rocker cover, if you might want to run the XR ecu as well as its mapped a little diffrent to suit the better flow and the XR fuel pressure reg. easy if you know what your doin could be difficult if you dont. probly better of spending your money on a mild cam after market cam, extractors and a 2 1/2 inch exhust.