Hey Iceman,
Pinball is right, but you also can get an answer to your questions. As for the SPADs, you might want to ask on the SPAD section of RCU, you'd probably get more help re. actual SPAD building. I built one (tried several times on the wing to get it right...), and found that sanding the coro surface, then wiping with alcohol is the way to go to prep the surface. Then glue with medium or thick CA. You only need to do it where there are glue joints. As for radios/engines, I would be more careful on Ebay than on RCU. PArticularly with radios, you need to make sure it is still a legal radio, and some people on EBAY might not know the difference. I personally think you can get used/nearly new stuff from guys on RCU's classifieds, and save a few $. As for brands, everyone has a favorite, I use Futaba radios and OS engines, but that doesn't make them any better than other good brands. The thing to do is narrow the question down, and maybe ask it in terms of what might be bad about a certain engine or radio. If you ask what is the best, you'll just start a debate and never get a definite answer.
good luck!