yes mk5 and 6 looms are different yes you can run it without PAS ABS etc plugs connected. and yes you can run a mk6 engine on mk5 loom and ecu the engines and sensor plugs are all the same, i have done this on my mk4 as i stupidly left the keys in the mk6 i broke by mistake and by the time i called my mate who was weighing it in it had been crushed doh!!