just looking at air intake/filters. i'm running an F20c engine (honda s2000) it has a 70mm throttle body intake. will be running stock (240bhp) this year then poss FI next yr(320+). looking for an intake system. any suggestions without spending silly money? thanks bobster

Which bit of the system are you looking for? IE, super/turbo charger to TB's, cold air feed, or other bits? Most of it you could make/have bent from suitable tube or pipe, and the plenum could be folded ally sheet that is then welded together.

it's just the cold air intake. looking at conical filters. wondering which was the best route to go. either
1) Cold air intake through hole in nosecone - through filter into plenum
or
2) Conical filter sitting behind rad - this will obviously draw in warm air.
will this make any real difference to the engine performance?

Cold air is a nice easy way of gaining a few extra bhp for free, and you'd be silly to ignore it. Part of why my carbs hang out in the wind! If possible, you want the filter to have it's own air feed, ie not the air behind the rad, as it will be warm/hot. Is it possible to fully duct your rad (thus making a more efficient use of the air, and having the filter with it's own duct?