I'm deffo no expert as i like bits of both versions..however the wiring and plugs seem to be the same.. the difference lies in the light unit itself..i put mk2 lights on a mk 1 with no mods at all and alls well so would imagine putting mk 1 lights on a mk2 would be the same deal..i was fully set up to swap over the headlights too as a lot of people have,but talked myself back out of it..i like the way my car looks atm and after upgrading all front end bulbs to nightbreakers/silverstar diadem etc i quite like the "just turned on the sun" effect ive never had in any mk/ph2 mera ive been in on country roads at night..even with supposed hid conversions...its all down to what you like i guess