definatly go for the rwd jdm manifold, as for the gte you will need a custom plenum for the qauds anyway which will cost uber $$$ on top of the price of the quads, and probably not much gain, you'd be better putting a 7m-gte tb on the 4a manifold or something, as for cooling, if your rad is in good condition it should hold up well, however, for the extra piece of mind you could always go for something like a aftermarket 'performance' aluminium ones for the ae86's (i think pwr makes them or something) and a couple of powerfull thermo's with a shroud.