I have a quick question, after reading some random stuff on RB site, it said that I have to have back pressure tube for the 6 port to work, but I'm thinking about getting the Bonez racing pipe, it doesn't seem to have the back pressure port, will I only have 4 ports then?

 

Check these current topics:

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/running-test-pipe-instead-cats-644675/

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/need-help-auxillary-ports-551120/

There were some typos until recently on this stuff on the RB site. I was confused and emailed Jim Langer at RB about it and he cleared things up for me and fixed the site a month or so ago.

The S4 RB pre-silencer or S4 header has the pick-up tube for the 6PI actuation, not the downpipe.