Last year my 94 TT went on the dyno for emissions testing with a manual boost controller, BCC, NGK plugs, down pipe, Gt-Spec exhaust and Greddy filter. It failed fucking miserably
. For the second attempt I put in my 3 inch hi flo Random Tech cat and took out my boost controller (hoses back to stock) and it passed. If you throw it on with a single turbo at the least you will need a hi flo cat in place to pass. I don't think there really is visual inspection in NY, I never had a problem.