I bought a plasma cutter years ago, but I ran a welding shop, so I used mine a lot. The 1st one I bought probably 15-18 years ago was a $900 Century brand and it lasted 10 years before the cutting head plastic got broken. The replacement head and whip (the only way to get a head) was over 1/2 the price I paid for the whole unit. Instead of spending the money on a new head & whip I put the money towards a new $1600 unit. The deal with plasma cutters is that whatever they are rated at means they will cut about 1/2 of that thickness pretty quickly, but as you get nearer the rated thickness, they get real slow. One rated at 1/4" cuts 1/8" very well, if its a single thickness with no air gap, but pretty much sucks cutting 1/4" or even sheet metal if there is double thickness with a gap between the two pieces of metal. I worked in my welding shop for 3-4 years before I bought a plasma cutter.

A Dakota frame is about 1/8" thick, unless you happen to be cutting where there is reinforcing and it could be double, or more thick. If your cutting straight lines, a sawzall with an 18 tooth/ inch blade will do a nice job, probably faster then a cutoff wheel. If you don't try to force the sawzall blade, you can get a nice straight cut with them as well. Measure twice, cut once. I usually cut with a little extra material, the clean up the edges with a grinder when I can. Clean edges both inside and outside on both pieces makes for a much better weld.

Good move on the 2007 Hemi with the joining parts and going with a Hot Wire harness. I think you will be happy with it. Gene