Honestly here is what you are looking at to do those things to your 318i. Yes you can spend $700-$1000 after labor to get springs and struts to slam your 318 or $1,200-$1,500 to get coil overs. Then you can get the M3 bumper or other bumper, some side skirts, a tasteful rear spolier for another $1,500+ after paint. Then you can buy some Recaro seats for ??? or M3 seats in good condition for $750+ easily. There is no Turbo kit for your car, so after getting it tuned and sourcing the parts, sourcing more parts because the setup doesn't work quite right and then retuning etc you're out another $5,000+. So lets see, that's reasonably close to $10,000 after the cost of your car. If you had $10,000+ whatever you paid for your car you would be in a nice E36 M3. That doesn't even count the wheels/tires, a reasonable head unit or speaker upgrade, short shift kit, brake upgrades, or any other engine/exhaust work. So you're really looking at perhaps $15,000+, plus the cost of your car. What you will end up with is a rougher riding, maybe as fast, less traction, worse driving car than the M3. Basically a lightly modded civic will always be faster in a straight line than a 318i. You'll out handle them in tighter twisties if you have some skill.
I would recommend following the same path I ended up taking, hold onto the 318i while you save that money and then buy an M3. There are some members here with very nice cars that they build, furious come to mind foremost, but they took a lot of time, money and know how to get there. You may be willing to do that and to find info on people that have done this you would have to go back litterally years of the forum posts to find when they did it and almost as far to find the last time some one was actually answered with these requests. Its tough if you really want to do it though start digging.
But here's some freebies just to put something possibly helpful.
1) The best suspension questions/recommendations have been answered a lot H&R with Bilstiens.
2) The software has been answer many times and can be googled easily Conforti or Dinan.
3) Cold air intake not worth it by itself but also answered K&N FKIP (or whatever those letters are), some people will say Conforti or even fewer cosmos.
4)Exhaust UUC, forgot the other popular option but can be searched for.
5) Rims, I personally don't care, I like the M3 wheels the best.