I had a custom made one from powerflow exhaust... £450 quid
Trying to find something sporty for a bravo is a nightmare and pricey so I had a cat back system made up!
With the amount of modifications you're looking at doing to your Evo, it's probably cheaper to sell up and buy an actual Abarth. I'm not having a go, just think it'd be better and easier on your pocket.
Plus you don't have to declare modifications on the Abarth to your insurers, as they're already on. The things you're wanting to do needs to be declared otherwise it's as good as having no insurance at all if there's an accident. They'll take one look at your new bits and clamp their wallet closed.