Yes this gun is for Clays and essentially I was trying to find some sources to get my existing barrel to have it modified as opposed to buying a REMCHOKE bbl. I wanted to contact those companies to find out the cost, but it seems the consensus is it's about $150. Based on that, I will most spend a little extra and buy a REMCHOKE bbl then sell my 30" VR full.
Assuming you have a Remington barrel, I would really suggest that you measure the bore before you send it out to anyone other than Briley or someone like Stu Wright putting in Briley thinwalls. Remington bore sizes tend to be all over the map. Briley will roughly match the thinwalls to your bore to ensure the proper constrictions. Folks installing others such as Tru-chokes might not since they are made to fit a nominal bore of .730 (I think). FWIW.
BTW - Mike Orlen is another guy to consider for installing tubes.
If you are going to use this gun for sporting clays, I strongly recommend that you get the 28" light contour barrel, and not the standard remchoke barrel.
Remington 1100 barrels are notoriously heavy, even the 30" light contour barrel makes the gun noticeably muzzle heavy.