Which type rhead did you get?? Doesnt make sense.....Is it a k20 type r, a b16b type r? or a b18 type r? Jun internals (retainers and springs) really arnt worth the money for type r cams. The only advantage to a B18 or B16b type r head is the double valve springs and more aggressive cam profile, they are also ment to be hand finished (ported) but when you put the two heads next to each other ther really is no differance. As for which car to put you motor in, it is up to you, the crx is lighter, then a hatch (eg) and your 2000 si is the heaviest. Just think power to weight.
BTW, the b16b and the b18 type r intake manifolds are both the same as the skunk 2, as for the headers the JUN and the TODA are good, but it all depends on much you want to spend.... do you want a 4-1 or 4-2-1?