Exhaust pipe build - Stock manifolds

Is there a benefit to running an X pipe, or balance tube, when also running stock manifolds?

Car is a 98 Camaro with an LS1 and T56 Magnum. It was built to run American Sedan restricted prep in SCCA, and I must use the stock exhaust manifolds.

Exhaust has to run behind driver's seat, but it doesn't have to run out past the body.

The primary reason for a "X" cross-connection is to share the exhaust gas path between the mufflers further down the system to reduce back pressure and noise.

It would seem you are allowed to run a straight pipe system, where mufflers aren't used, so any benefits may be minor.

Depending on the specific wording, you may be allowed to use "stock" exhaust manifolds from a different model/engine that is better flowing - or at least be able to clean up the castings internally to smooth the gas path and, hopefully, reduce resistance a little.