I bought my 870 Supermag last spring...I'm currently shooting a Kick's GT choke with 3.5" Win. Supreme #5's. Its been a pretty good combo so far...I killed a nice longbeard@ 45yds. with it last spring and put a coyote down in its tracks without so much as a twitch @35 yds. However, I too am think about upgrading to get a tighter pattern. There's always that one time every spring where you have that gobbler that you've been after all season hung-up at 50-55 yds. and you wish that you could reach out and touch him. The thing that worries me though is having a pattern that so tight that you miss birdsat 20-30 yds. You can only kill a turkey so dead I guess.

Check out these chokes...they're the new rage on the NWTF forums...

http://www.indiancreekss.com/home.htm

Good luck this spring....