At 170lbs. the PL #'s are def. respectable. Like Dave mentioned, it will be crucial to train w/ someone you can trust to really watch your form/depth and also get some video. From what I have seen at the gym I train at, probably 95% of the bench press attempts would be no good in a competition. If you are going to compete in a "stop and go" bench competition it could take several sessions to feel comfortable, at least that was my experience! I never did the chest bounce thing when I benched, but I did more of a "touch and go" and it was quite a bit different than stop and go!
Good luck with it if you decide to do it and keep us posted!