Advices needed to build a custom 911 2.0-2.4 muffler

[alexARC]

Hello Guys

We're thinking to build a custom made silencer for 911 with heat exchanger.
The design would be a R replica with 2 outlets below the rear bumper.

Now, the difficult part is inside of the silencer. We'd like a good sound and (slight) performance improvement (at least not performance drop).
I've crossed this kind of design few times on performance exhaust:



rather than conventionnal straight inlet-outlet design like the original race car.

What's your opinion?

Thanks