[stephen low]

Geof

I've got the same. Used the cats off the std Ford AU system that was attached to my engine and have either 14 or 16" mufflers tucked up at the rear beside the fuel tank.

Am also running crossover but not sure if this helps or hinders noise.

At idle I have a relatively quiet throb but it has a reasonable bark once pushed. Also only ran a 2" system to help keep noise level and back pressures in check.

You might be surprised once you test to required specs. Worth doing in advance so that you can ensure you present a noisy worthy car during engineering.

I'd be keen to know what levels you do end up measuring!

Cheers