Don't buy crappy ebay coilovers. If you are modding as much as you can for the little amount of money you have, you will be very disappointed with the outcome. You get what you pay for, and if you buy crappy coilovers, your ride quality will greatly reflect that. Do it right the first time and invest the proper amount of money for what you are doing, so you don't end up down the road buying what you should have bought in the first place.

If it were me, I would skip 1 and 2 like I previously mentioned. 4 can be easily skipped too. Buy some nice coilovers like GC or similar, keep the stock speakers unless they are broken, and invest in a good alarm system. If you have money over, you can think about the others, but until then, I would leave them as an afterthought.