wanted stainless steel exhaust system with or without 421 manifold to fit 3f GT

I had a look about recently for my GT. The ebay SS manifolds have fitment issues apparently, and Ashley never answered my email. There are only 4-2-1 manifolds on the market and really you want a 4-1, so i concluded the only way to do the manifold was to make it myself. German websites list the rest of the system, but nobody supplies the cat. Basically it all has to be made from scratch by someone, with or without a sportcat. You can cobble together a frankenstein, but the results will be poor.