Mine went on an old Fiesta I once owned people were ducking as I was driving past :lol:.
The Piper manifold and sports cat is decent and around £400-£500 iirc. Japspeed I've heard are O.k but are a 'stumpy' manifold and don't give gains as good as other manifolds, such as, the Piper or DC Sports etc. But if you want one with a sports cat your limited really because I've only ever came across Piper or Mugen. If I change mine it will be for one of them.
It's not just the manifolds off Ebay it's most things, brakes, suspension etc they all seem to be cheap tat (Hence quality issues). My mates bro got an ITR DC5 and got grooved discs, they cracked within 300 miles, I've known others who have bought coilovers and quality is shocking, most people change them then because they are crap, buy cheap buy twice.
As for the Sportex a few have got them on here just use the search box loads should come up, I've heard some have had to chop them to fit them but they don't last as long as stainless steel hence the price.
Another option is the custom route but I didn't have the best experience when I had a catback done so I wouldn't really recommend that route.