Exhaust box size? Rally car

[kipsy]

Hola, I'm having an exhaust built up next week in Prospeed Cardiff. The car is a 325 e30 stage rally car. It currently has a twin 2 inch(I think) pipes from the standard downpipe into a large bore x pipe and then into a standard scorpion system where the only silencer is the large scorpion back box. I'm looking to renew the back box and pipes for larger bore (ready for m52 change in few months etc) to increase performance and add bit more noise. ( it's way too quiet) as the silencer is being made any ideas what size to go for? The car had a standard front half system before with standard silencer and just two cherry bomb rear silencers with sounded great but broke up over time. I would love to get the sound as it was before.
Ta

[alan1272]

ordered some simons boxes from tweeks for my 318is rally car, there's a large selection of sizes and pipe diameters. you can get ones with double pipes in and out. i'd guess you're going for a twin 50mm system?

two smallish boxes and it does 86dba on the 0.5m noise test.

[kipsy]

Ok cheers for that. I'm only running one box and can be louder than that as stages only now due to 6 pot engine