V8 90 CSW Exhaust system

I would like to improve my exhaust system but as you can read below I want to KEEP the 3.9efi Range Rover manifolds SO what system will give me the best sound from this V8????

At Present this is what’s fitted
The exhaust manifolds are standard 3.9 EFI Range Rover, but have been machined to match the exhaust ports on the head and as such have TVR big bore gaskets fitted. The remainder of the exhaust is Range Rover until the centre joint where it is then 90 TD5 and rear TD5 box. I also have the round RRC cross member fitted to allow the exhaust to be fitted correctly for clearance.

any advice?

If your exhaust is sound, the cheapest option would be to remove the rear section and fire it up. If you like what you hear, find a replacement section without the rear silencer.

I'm not sure what you mean by big bore gaskets being required. Standard heads and 3.9 manifolds both have ports slightly smaller than standard gaskets so port matching would not require them unless you also have tvr / ported heads