Most powerlifting organizations are drug tested.
you could lift in the USAPL and be pretty sure that the people you are competing against are drug free. But honestly you can't ever really tell who is on or who is not.
Competing is good, I do it, and recommend it, but you really need to compete against your own personal records. If you get caught up with trying to beat any one but yourself, then I think you will be disappointed. For example, I benched 110 lbs more on December 29th, 2001 than I did on July 7th, 2001 at about the same bodyweight. That makes me very satisfied. I blew away personal records every single week during this time period. That was great. However, if I am just worried about what other people are doing then I have to realize that even though I put on 110 lbs on my bench, that George Halbert can still outbench me by over 200 lbs, and Powerlifterjay can outbench me by well over 100 lbs. If I compare myself to these guys, I don't look like much, but compared to myself 6 months ago, I am a freaking animal.
As for the gear, it does help, but in my humble opinion, it does not help nearly as much as non drug users think. Gear will help you put on size and will speed up recovery ability pretty good, but if you are on westside's program, I can tell you from personal experience that you are going to make gains on gear or off.
Best of luck and hope this helps.
B.