Best Spot weld drill?

I have had decent results with the HF units with the only down side being grinding the center down after the panel is gone. I have also used a plasma cutter. The Dewalt bits and the Snap-on / Spot Eze, both of which work pretty well but tend to go through both pieces too easily. I'm getting ready to do lower quarters on the 75 Dart Sport and will probably use a combination of the HF and a 3" whiz cutter depending on how recessed the spot welds are...