Most tunable hot hatch....
Fiesta ST with a supercharger?
Forged internals
Uprated Bearings
Big bore Milltek exhaust system and manifold
Cosworth Duratec inlet manifold
60mm throttle body
Jamsport spec cams + valve springs
Various other fettling
That spec has seen up to 384bhp on the rollers, giving an absolutely ludicrous power to weight ratio, and the likes of Jamsport and others are continuing to develop further - the 384bhp car was still a 2 litre but you can convert to 2.3 or 2.5 litre capacity, add throttle bodies in a custom manifold, then they're creating a 2.5 Duratec Turbo...
Such a car would needs serious work in terms of brakes, gearbox (which is very likely to break and crys out for an LSD) and so forth as well for longevity, but they can be made seriously quick if you're mad enough to splash more cash on the engine and tuning bits than the car cost in the first place...not too sure on drivability but for a car of its type (2.0 'small' hatch) I can't think of another that has quite such a range of parts and conversions available.