So long as you use appropriate automotive-grade paints, and apply them precisely as instructed, the result will be great.
A computer-specific issue is the metal inside the case. It is full of impurities that will fish-eye paint and make it difficult to get a smooth coat. Preparation is critical; more-so than usual. If you can blast it, do so. If not, get as much sanding done as you can. Use a Dremel with a wire brush if you've got one to scuff the bits that you can't get to, or just be patient. Degrease it thoroughly.
Any kind of acid treatment you can manage will help. If you can't do that, get serious with the pre-paint spray or mass air flow sensor cleaner. Use a nice self-etching primer. The stuff NAPA sells behind the counter is great, but don't use it in a confined area. Most of the time that's advice that people ignore. Do NOT ignore it this time. That stuff is nasty as hell.
Use those light coats as specified. It's very important. You'll never get a good finish if you don't. Be sure to clear coat things to protect them where you can.
Plastic can be a pain, because people have usually wiped it down with various conditioners containing silicone. You'll need to degrease plastic as well, but it's a balancing act between cleaning it up and damaging the surface, so be careful. This should always be cleared. Do it right, and the result will be solid.
Spray cans can produce finishes rivaling those of proper paint guns. You just have to take your time.
Don't forget to hang your parts at good angles to get even coverage and avoid buildup at edges.
