So true about the guide bolt, I shredded a pefectly good BB thinking the BB was stuck. one time.
You can get even better leverage by putting the BB removal tool in a vice grip and turn the frame instead. Make very sure which way to turn your frame so you won't end up cracking your BB shell.
I had a seized/galled alloy cup Shimano Cartridge BB stuck in a Ti frame and I filled the seat tube with PB Blaster it took a can and a half over two days but I was able to get it out using a longer 8mm bolt and washer to hold the BB removal tool in the cup....pipe wrench with a 4' pipe over the handle of the wrench for added leverage. Make sure you back out the bottom bracket cable guide bolt a few threads many times they thread in and hit the body of the cartridge BB and act like a set screw making it more difficult to thread out the BB.
Rattle canned MB2