throttle bodies work awsome on that engine with a aftermarket ecu e.g omex.
then exhaust should sort it out to closer to 200bhp
somewhere like www.Minister-power.com are duratec specialists.
thats the route i'd go if i still had my st170.
Full exhaust system including cat and manifold etc will see a small gain as the exhausts on Ford cars seem to be very restricted. Also airboxes are found to be fairly restrictive so a decent induction kit would be another good mod. Also i'd personally look at lowering the suspension on Eibach springs to make the car hold the road alot better.
Id be wary of out-of-the-box remaps on N/A cars as they seem to be the same price you'd pay on a turbo'd car for some very slight if any gains. You'd be better off with a custom remap once you have added a few mods if you want to go down that route.