I have a real hankering for a 4c at the moment and is on the radar, very surprised it came out on top (although not by much), just a remap takes it from 240 to 280hp which is the most you can get from the standard ecus and a pretty healthy jump, by all accounts the ecu for the gearbox will not accept any more power than 280hp from the main ecu, a race ecu and you are up to 320hp, hyrbid turbo 340hp and twin scroll 380hp + all on std internals.
Alfawerks are developing a crank to take it to 2.0l or you can forge a std one, being that its just the aluminium Giulietta engine you could pick one up from a scapppy for 50p and forge away in the background.