Use an eighth inch drillbit first to start a dimple, then go to the spotweld cutting bit. It just makes it easier to stay on the spotweld. Any tooltruck should have them, an autobody supply store, possibly a welding supply store, Tacoma screw, harbor frieght. They're all over. Or make your own with a regular 1/4 in bit and a bench grinder. And true true on the slow thing. High speed drills will eat right through on the first couple, then your bit will be toast and need a resharpen. The only bolts holding it on will be the body mounts to the frame, as for how many spotwelds, it's always different and they're never in exactly the same spots. You'll see this if you're welding in a junkyard one. Just take you're time and find them all, there should be a half dozen or so connecting the upper tie bar to the upper rails, and probably 10-12 per side connecting the baffles to the aprons. If you drill too many, you can always weld them back up. If you try to rip it off without drilling them all however, you're going to make a mess.