[Frederico Dias]

What Stu said is right.

Get a decent Air Filter and Exhaust system, both will come to £300-400 for 5-10bhp.

You're looking thousands of pounds to get more, my 1.4 ZR Rally car is 150BHP, and has had about £3000 spent on the Engine

Do you think it'd be worth it to make a custom intake manifold and fit individual throttle bodies from a CBR 1000? Because I reckon it'd not be very expensive barring the fabrication