2.0 is a good base to start on mate. They do respond nicely to tuning. Once you get a 4-2-1 manifold or similar, cat-back, preferably an enclosed induction kit or ST setup, and some mapping on it, they really can hold their own and can upset most of the smaller engined BMWs/Audis/Mercs. Put it this was I have a 1.8 RR'd at 145bhp, 127ft.lbs. Sat bumper to bumper off an Audi A3 1.8T up to 95mph (airport runway) beaten E46 320i's before, mullered just about every single C class coupe sport as they weigh about 9 tonnes and have fuck all power even the most powerful models. Had a go against a modded VTS and I couldn't pull away from it. They are nippy. But the focus has got torque due to being a 2.0, really enjoy my mid range punch. You won't be disappointed imo. What else are you looking at anyway?