Thanks Alax and yes, I did it all with a spray can. I've painted stuff with spray paint before but never a car. This was the biggest painting job I've ever tackled and to be honest, when I started sanding it down I was pretty scared that I would be buying a new bumper haha.
Here's a fairly detailed write up - if you have more questions I'd be glad to answer.
Sand everything down. Rub with a wax/grease remover. Fill with glazing (bondo). Let dry and sand. Wipe it down again with wax/grease remover and a tack cloth and spray first round of primer. Let dry and then sand everything with around 300 grit.
Noticed a BUNCH of imperfections. Fill again with glazing. Let dry and sand. Use an air hose and compressor to clean it off and also a tack cloth. Round two of primer. Let dry and sand with a slightly higher grit (320). REMEMBER, MY BUMPER WAS A TOTAL NIGHTMARE SO YOU MAY NOT NEED TO DO NEARLY AS MUCH SANDING OR FILLING SO YOU COULD PROBABLY START WITH A MUCH HIGHER GRIT PAPER.
I repeated step 2 at least 5 times. I went through almost 5 cans of primer to build up some imperfections. You need to be patient and get a shop light you can hold in your hand to survey the area very closely to find all the little pin holes. When I was happy with the primer, I wet sanded the whole thing with 1000 grit and it actually started to feel like a car again - very smooth. I aired it off, used some more wax/grease remover, and a tack cloth to clean it. Make sure it is very very very clean - it pays off in the long run.
I sprayed my first layer of color and used nearly an entire can. Since it's metallic, you need to stay far back to make sure the metallic look stays consistent.
After it dried, I wet sanded the color with 2000 grit and once again was very meticulous about cleaning it. I aired and tacked again.
I put on another light mist of color, let dry, and gently wetsanded with 2000 grit again. I aired, tacked, and used one final rub down of wax/grease remover.
Finally I sprayed a light coat (staying at least a foot away from the car) to make sure the metallic flowed well. (I think I could have done this slightly better because there is one spot that looks a bit more green and not as 'metallicy' but it's not that noticeable - i learned something for next time)
I let that final coat dry for about 25-30 minutes and sprayed the clear. I DID NOT DO ANY TYPE OF SANDING TO THE FINAL COLOR COAT BEFORE THE CLEAR. I JUST BASICALLY CHECKED IT FOR DIRT AND AIRED IT OFF.
I sprayed the clear and let it dry. I bought catalyzed clear coat from paintscratch instead of the 'regular' clear coat because they claim it is harder (and obviously I need harder to help reduce the amount of rock chips). They also claim it requires less work and should be pretty glossy without polishing. If you use 'regular' clear, you'll probably need a buffer and some rubbing compound (I hear 3m makes some good stuff) to get the shine up.
Some notes:
I bought a rustoleum spray can holder thing so you can operate the can more like a spray gun and you finger doesn't get tired - it worked awesome and allowed much more even coats. Cost about $8 bucks and well worth it.
For my color and clear coats, I wet the floor and also laid down plastic. I also had some fans running to keep circulation going.
Use plenty of lights. I had 3 spot lights on my car as well as regular overhead flourecent lighting in my garage but I also had a work light which stayed in my left hand while the sand paper or spray gun was in my right hand.
Both the primer and color sprayed a bit thicker than I would have liked but not a big deal. The clear however sprayed damn near perfect.