Hey guys I just installed the ultimate racing dual catback on to my X. That's the only thing I have on my car right now other than an hks drop in. I have a leak that I can't figure out between my stock cat the and the Midpipe. Will that cause me to run rich or anything? Is it a problem I should be worried about or am I just worrying for no reason?

 

If it's post cat (and therefore after your O2 sensors), it won't cause you to run rich/lean. Only time you will have a problem is if you're leaking prior to the O2 sensors. In that case, the mixture reaching the O2 sensor will be leaner than it really is and therefore, your ECU will richen up the mixture to compensate

 

Did you reuse the stock gaskets? It's good practice to use new gaskets (make sure you get 3 inch gasket) everytime you change your exhaust. Could also use a gasket filler material