Well insurance on the valver should be cheaper Lewis, dunno what group they are but valvers are fairly high, 15 iirc?
I'd personally get a valver as insurance is not a problem at my age, but the reason I'd get one is for the wider arches and more aggressive stance. If your hell bent on finding a minter though best bet is get whatever you can find thats the best for the money... even if it's an RSI it's only £150 from any none rip off garage to get them to just swap the engine over as F7P's can be picked up for nowt... in fact F7P head and Megane/Williams F7R BE (£300ish) would make a great sleeper and track toy.
By in gear, what I mean is say both cars are sat in 4th at 30mph, the RSI would win handily here due to the torque, valvers need to be driven on cam, therefore in gear they suck, so normally you'll find yourself dropping down a gear or two