i kept stock pipe diameter and it popped ONCE when i was demonstrating to my fam. it was cold. has never popped since then
i'm gonna go on a limb here and say that performance is a bit improved, according to the booty dyno
feels
easier to go faster
my set up on a 2008 T:
the old stuff. i can go out and measure the 'outter diameter' and 'inner diameter' if you like so you can know f'sho and settle your curiosity?:
here you can see my stock piping on the right. the FM Y-collector on the left (now dirty/burnt looking). and then this silver piping they put in; kinda looks like they expanded (swelled) their pipes to fit over my stock pipes and welded it nice n strong, then butted it up to the FM Y. dunno if the $75 install charge included the cost of this piping
FM Y...
BULLET. again, i did not bring that turn down into the shop and i dunno if that was included in the $75 price. maybe someone forgot to charge me?
other various shots:
no more tip!
and more video. stock vs. bullet comparo. mostly bullet fwy driving: