I have a Tanabe 2.75" Downpipe and was wondering if switching to a 3" would be noticable? I hear that a 3" may cause some clearance issues with the bracing. I use the car primarily on the highway and around town. In addition, I was thinking about installing cams but may end up waiting.

 

The bracing "may" be an issue but nothing a few washers or spacers can't solve. I have the AMS TBE, and was required to run washers to clear the bracing. I also had to cut a notch out in my Beatrush tray for it to fit.

I cannot confirm that there are any differences with a 3" or a 2.75", somebody else maybe able to chime in on this one.

 

just read this commentary from www.roadraceengineering.com

Espelier Stainless Steel Down Pipe
Espelier Stainless Steel 2.75" down pipe. OMG! It's only 2.75" diameter! ¡Que horríble! Yeah, you will be limited to about 600 hp with "only" a 2.75" down pipe. But hey, it nicely fits all EVOs including MR and '05s and newer cars with active center differentials. We figured that was the important part.


With the 2.5-2.75" DP you'll have better low-end tq for around town driving...

 

Do a search on "backpressure" with "Zeus"...