Umm, depends on your budget, a set of suzuki gsxr750 bike carbas on a modified puma inlet with an aftermarket ecu will give a nice power gain. I was speaking to a few guys who ran 1.4 zetecs in rallying (good little engine for a 1.4 class), the rekon the bike throttle bodies, ecu, some mild headwork, high lift cams and tubular manifold cost about £2k and delivered 110 horsepower at the wheels.