My question is can I run a 180 vrs ecu on my 150 arx, my guess is that the numbers have to be the same, but a mate said it would work, first pic is mine 

I wouldn't really try it, from experience whenever I have done anything like that the pin layout is different and may cause power/earth's to go places they shouldn't do... haven't done this on a VAG but assume it should be the same...