I would like to get your opinions on what size you'd go with if you had the tools to make your own DP (because I do).
My current is a 2.5" v-band and full 2.5" exhaust. It'll probably stay that way for a while, but I was wondering...
I plan on installing a cutout in my exhaust, since I bought the car w/ most of the 2.5" intact, I figure it's a cheap way to make the 2.5" more efficient, as if to flow like a 3" exhaust would. (yes, it will be loud, I know this)
Now I'm wondering if I make my downpipe any size, and install a cutout of the SAME SIZE, then leave the 2.5" behind the driver connected, would that be recommended? I would prefer this method because it'll save money, save lots of time, and WTF would I do w/ half of a 2.5" exhaust system for a Miata once I take it off? Might as well leave it. Oh, and I can always cap the cutout and be stealth, which comes in handy for interstate driving.
So basically, would you recommend a 3" downpipe and cutout reducing to a 2.5" halfway under the car? 3.5" downpipe and cutout? Would a 4" downpipe even fit between the firewall and transmission/would it be worth it since the turbo exhaust housing is only 2.5"?
I would just need to buy another v-band and probably $80 worth of exhaust tubing to make another downpipe and midpipe (running no cat) of any size.
*Biggest reason I was considering this because the newb who made the DP for the car (before I bought it) welded the v-band to exhaust tubing about halfway through the arch of a 90* bend AT AN ANGLE, and essentially the DP is now the biggest restrictor in my exhaust.