Since im full of silly idas heres another. What if for exhaust I did just catless downpipe, long resonator, turndown before rear axles?
Here's a view of a custom system
I was thinking of running a resonator as long as possible and using a turndown where furthest flange is in the pic above. (pic is looking underneath towards the rear, the pumpkin at the top of the pic is actually the end of the transmission.