I have a mostly stock 87 RX7 GXL I was thinking about doing exhaust on. I see on Mazdatrix the Road/Race complete exhaust system is SKU 16451 for an 86-88. I found a system for sale that looks like a reasonable price that appears to be 16452 since its sold as an S5 system. Would this bolt up without modications to my S4? Any details I'd need to know? Also, I don't see a note about an O2 sensor bung, and I'd want to run the factory O2 sensor. Anyone familiar enough with Racing Beat parts to answer my questions?

 

The 16451 has the " back pressure pickup tube ". The 16452 does not. The 16452 will bolt up just fine but without the pickup tube your 5th and 6th ports won't function. You can search the forums about this and possible solutions as it gets discussed multiple times per year.