I think the H&S system uses the standard turbo discharge pipe, which is a bit of a restriction, without changing which you may as well use a stock system. Although I could be wrong, H&S may have now added one, but from memory they just have a downpipe that terminates where the standard downpipe sits... the discharge pipe is the part which goes from where the standard downpipe bolts up to the actual turbo.
Yes, really expensive, but that money spent is the difference between 360 bhp being made easily, and 420 from a 2.5 motor with a turbo, injectors, MAF kit, DPW and and a mild intercooler running the same boost on a well used engine and without the exhaust it is difficult to break 340 to 360 BHP without spending a fortune elsewhere.
Even still, its an expensive mod to swallow, but why few cars break the 400 BHP mark.
We invested a fortune trying to jig up our own exhaust with a couple of improvements over the fabspeed, but the cost of manufacture was looking close to the cost of a fabspeed, without even recouping the development cost, just as the 944 tuning market place shrunk, so it was put on ice.
If you are lucky, and if you buy at the start of the financial year, the costs are lower, as the import quotas for car parts from the USA will not have been reached, and therefore you are only looking at VAT and HMRC/Courier admin fees.
As the OP is in the shipping business, I think he can probably get one over hear at a reduced price if it is put in a crate with a few aircraft bits
