Actually you should still document your failure just to show others if something is not worthwhile, as I think Grant Woo said that he found 2/3 the time there was a "slight" increase in performance in the CM030 but compared to the TM 18c it was not as good. But since you say you have better gears then you should be okay.
Also again you don't need a stronger motor for that cm030 even if it fits or not, even that china brand motor in there is fine. You can try procuring the TM AEP motor though that is usually a hard find on its own as its usually not stocked or that it comes together with a MP7 Gearbox which can cost upwards of $100+
Anyway I think you are pretty much set, lucky you with the boneyard parts. All you need is to figure out the wiring of the battery
I am really for this project cause I wanted to do it myself but did not have the time plus I sold my CM030
which I regret
If you can figure the wiring properly you can hook up a 9.6v and if you put in those steel gears then your gun should be okay.
YouTube - cm030 g18c aep 9.6v intellect
The motor should be decent for now, if anything you don't need a new motor but spend it on getting that battery. Perhaps if I can find another CM030 I'll take on the project after exams.
Oh one last thing
DO NOT GET THE CYMA HI-CAP mag as much as you think you are saving money, it is complete crap because you are gambling 50/50 chance that it actually works, mine could not even hold BBs inside of it