The Evo will turn into a larger money pit and you know it. There is no kicking the GFCP. You will end up with an Evo version of what your 1g is now. If you are going to buy an Evo, might as well not lie to yourself and realize whats it's going to end up being(if you wanted looks/show only, you'd buy something that doesn't have the potential of making power.. there is a reason the Evo is THE option).
Oh, and having multiple cars that you are modding sucks arse, I wouldn't suggest it(I may be adding another soon :P.. I've skipped the GFCP and went straight to needles in both arms
).