I am getting ready to drop my subframe so I can get my new full floorpan installed. The problem is years ago I put in some bolt-on Competition Engineering subframe connectors that for some reason I can't remember I welded in on top of bolting them. I don't want to re-use them because I want some Hotchkis or GW's. Should i pull the entire frame out and then work on removing the connectors or cut the connectors out before I drop the subframe? Can I use my grinder to cut the connector? And what is best to get inside the frame rail and get the weld cut out and removed w/o damaging the frame?

I would take off the sub frame connecter's first. Where did you weld them? You mite be able to cut you floor out with them attached to it depending where you welded them. If you wan to save and resale them use a cut off wheel or your grinder.
Hope this helps Bob