Oh yea don't get me wrong if there is a fault code for it then its had it for sure . but what i was getting at is they run a safe mode when they fail and run a certian mix to prevent damage to the cat so you may find the idle issue is unrelated or may be related with a mk3 nothing is certian and they certianly love new parts espicaly coil packs .
think i just saw your car parked up in the greys road car park earlier about 10.30 ? looks nice if it was yours ! ,