I ordered a custom barrel from Remington for my 1100. I was able to get the forcing cone lengthened, middle bead in the rib, and screw in chokes for under $300. My 1100 shoots as good, or better, than a lot of the local O/U clays shooters. On one of my favorite sporting clays ranges, I actually did better with the 1100 over my Browning 325I because of the shorter barrel and faster swing.
I don't know what kind of shooting you are doing, but you can also taylor your loads to help yourself out if reloaded ammo is permitted. If you have to use factory ammo, you will have to run down there a couple nights a week and try different shot/choke combo until you get in the ball park.
Steve