how do guys get your cars to pass inspection i would rather not have to put the stock parts back on

 

If you're concerned about passing emissions if your car is 1996 or later all they do is check the OBDII port for any emission's equipment error codes. If you have no CELs you'll pass. There is no emissions sniffer test if that's what you're concerned about. I live in Fort Worth so other cities/counties may be different.

My 02 WRX is fully cat-less with the appropriate CEL fixes (resistor for up pipe and the mechanical anti-fouler mod for the 3rd cat O2 sensor) and it passed just fine a week ago.