exhausts

just dropped my car of to get its custom exhaust made/fitted 3" turbo down pipe/straight through silencer and 3" pipes hopefully it will sound like a beast

i also asked him to look at the manifolds and the first thing he said is how restrictive they look,i mentioned about cracking on after market manifolds he said that wont be a prob as he would use a flexi joint on each manifold thats the good news the bad news is he wants £900-£1000 thats fully fitted + vat etc think they might after come next year

For that money it would be better to go for twin turbo manifolds, and reap far more from the engine. Less lag and more top end

Not that I'm planning on doing anything like this! But isn't the Venturi LM400 a twin turbo PRV? Is it possible to buy spare parts for these cars and fit them to a GTA? Or are they all hyper expensive, one off, made to order fabrications? What differs from a GTA to make them twin turbo? Just curious!

Yes, 400GT is twin turbo but its 24v so the exhaust ports and mounting is different.

There is nothing on the 400 that is particularly sophisticated, so you could get bits made to a better standard. The manifolds were pretty substandard, the turbos were small T25's (lower spec than used on Rover 800 turbo), engine management was remapped Renix ecu with standard GTA loom, igntion module etc...