Thanks for all the replies.
In the world of 3rd gen RX-7's, one of the common tricks is to replace the pre-cat with a downpipe for a little extra hp. When you go for inspection, you put the pre-cat back in. From what I've read it looks as though it may even be possible to put in a second cat on the SR20DET 240 for a day.
As far as the Silvia conversion is concerned, I don't plan on stopping with the SR20DET. It's just that body work and other little things don't tend to raise flags at inspection time.
Thanks for the friendly words, NiteKids. When I'm done, I'll send you a picture of my Silvia parked next to my RX-7 Type RZ.
