I have a mk3 @ 11.5 psi with a full three inch exhaust and a 3 inch downpipe. mk3 run on two cats if i put the first one on which is the only one i have including the 3 inch cat back will i be able to pass admittions.

well this one is for someone on your side of the world to answer
we don't have emissions here ;)

if someone doesn't answer within the next day i'll find out for ya :)

Thank you very much

depending on where you live (pretty much anywhere except california), I wouldn't even bother with the first cat (the one on the downpipe), and the next one I'd gut. the car will run fine that way, as the only o2 sensor is on the turbo elbow.