OK, seriously this is what I'd do if I were building an exhaust from scratch.
I would build a 3" directly off the header, this would go back 2 or 3 feet and merge into a 3" "cut-out" electronically controlled from the cockpit. As soon as it exited the "cut-out" on the most unrestricted side, this small length of 3" would be your side exit. The other exit out of the cut-out would go straight back & would be EXTRA MUFFLED, as in totally stock sounding. The way I'd use this is 90% of the time I'd drive around "in stealth mode", until I needed my 3" free flowing side exit; then I'd unleash the FURRY !
Rob #43 ITS/ITR/STU, BMW 325I, STU LAP RECORD
SUMMIT POINT WV 1:24:229 SCCA
(DynoDynamics https:vimeo.com/8486878 Dyno Video)
"Chance Favors The Prepared Mind"
I BUILD SUSPENSIONS (Consult) FROM MILD TO WILD FOR RWD & XI E46's
I Know How To Fix The Rear "Bouncing" Problem On Your Cheap Coilovers Like: Jom RL FK SE & RK.
Originally Posted by RacerX
Nitrous is a little trickier than boost, but it's not the spray that kills motors, it's STUPIDITY!!