I've read and been advised that the longer & tapered the runner = +ve effect on torque it will have. My old ITG set up was 40mm worth of spacing from the bodies (to clear fuelrail) - back plate - 40mm trumpet - 65mm internal height filter (15 between filter and trumpet) and could just about shut the bonnet! Will be using same spacing off the bodies again, at least 90mm trumpets and at least an inch space inside the filter.
Can't say I'm surprised about the mold cost tbh, bit of a limited market too, dread to think what the genuine items cost you! We've been talking to a composites place about doing roofing panels for canopys who've also done car parts will take a bulged out wing down there and see what they say.
Interesting, mine was gone at the end tanks too, not what you'd expect for a quality product, they wernt rapid making it in the first place, pop it off to them during the winter methinks.