Finding a good bumper is definitely the hardest part. I just backdated my rear bumper last night. It's not difficult, but you do need to poke holes in the right places
There are posts with pics of hole locations and measurements. These will get you very close, but measure for your specific car. I found that they were slightly off when I measured the hole locations on the car vs. the spacing on the bumper.
It's not hard, just be patient! Also good idea to get a round hand file so you can widen the holes as needed.