why not get a front cut?? that way you get the engine, ECU, harness, brakes, instrument cluster etc all included. Trust me, makes the conversion so much easier.
I doubt that a simple db test will be enough to clear the defect. As your exhaust is not standard anymore, it is deemed a modification and will need to be engineered. Your engineer will be able to do the certificate and the db test all in one. He can also engineer your pod too.
It only costs about $500 to get your whole car engineered, so my advice would be to get an emissions test done first and tuck your exhaust up so that its >100mm. Then just take it to any engineer. There you will get a drive by induction test done (for your pod filters), a stationary noise test for your exhaust and the engineer should pass everything else, assuming that the emissions test is OK.
Answers to some commonly asked questions:
1. It is a 5 speed manual
2. No, I have not turbocharged the NA engine. A full RB25DET NEO was transplanted in from a Stagea.
3. Yes a swap may be considered. Mainly looking for a late-ish model WRX or R33 GTR. Cash adjustment may be required depending on model and condition.
Thanks,
Brett