yea i didn't know for sure weather or not there were any size differences. never worked on an NA.

The cat's are different. The GTE's is large and flows a greater volume. You should be able to bolt it up just fine though, the flanges are the same size IIRC, just might have a little trouble lining up the exhaust gasket so there aren't any leaks.

well with the larger cat on an NA.. would your emissions test suffer?

Not at all. They're built the same way. The GTE's is just larger and as such has more catalyzing surface area capable of processing more gas.... could *possibly* make for even better emission scores. The only real reason they didn't use that one on the N/A's too is that the materials inside are so costly.. so, you go with the smallest you can get away with.