I thought about going the SSI route as well. What really kept me from doing it was the potential of breaking off exhaust studs. The Dansk, bypass and Steve Wong chip I have installed have made an improvement in performance.

So, you're saying the consensus is that SSI's, the 3.2l specific ones, provide no performance increase other than the obvious deletion of the cat on an '84-'89?

you can go on 911chips.com and check some dyno data.ihave read somewhere that the sw chip,fabspeed cat bypass and a sport exhaust were better than ssi set up for 3.2 but not for 3.0.i put ssi on my 3.0.

My 2 cents:
I'm currently installing a fabspeed premuffler/cat bypass, Dansk 1-in-2-out and SW chip. The fabspeed premuffler is actually a cross between a euro premuffler and a straight pipe cat bypass in that is does contain some baffling, but it is a straight-through open flow path.

After much research, I expect the "power at rpm" improvements from the chip and the premuffler, not so much from the sport muffler. The muffler is being done mostly for sound & looks.

BTW, my thanks to Buckterrier for posting the photo. It's quite helpful, as I'm also working on a bumper mod and deciding where to mount the new license plate lamp assemblies. Like him and unlike most other photos posted on this site, I've decided to keep the rub strips when eliminating the bumperettes.