dense air in england... I'd almost prefer a turbo, but if you supercharge it, use the 7m-ge, higher compression=more HP w/ less psi. I dont know of any kits, or anyone who has done this... either way, good lusk w/ your endeavors.
ps: before you do anything I would reccomend a metal head gasket, and some hrp head studs torqued to ~72ft./lbs.