The Librands exhaust does not swap the Cat or the Manifold.. although hi-performance versions of both are available.
Richard Thorne market a set of S1 Manifolds and a high-flow cat can be purchased from most performance aftermarket companies.
I have had 2 cars with Librands exhausts fitted... I fitted the first and the second car already had it fitted from when I got hold of it.
There are 2 variants of the Librands exhaust... 82-85ish db and 92-94ish db. There is a couple of hundred quid in the difference both are in the £1,200 - 1,500 region from memory.
The quieter one is more of a woofle where as the loud version can become quite barky... if my second Aero did not have a Librands then I would have personally gone for the louder one.. but then I know this is my personal view and is not necessarily shared by everyone...
