The things you should probably have to undertake the jobs you mentioned are: 1. Air compressor large enough to run a die grinder with a cutting wheel; 2. Several thin stainless steel, very strong, "putty" kinves and chisels for breaking free the weld beads you have ground down with your die grinder (a spot weld cutter is nice to have , but you can remove spot welds with a regular drill bit if you are careful); 3. a 41/2 " high speed electric grinder (90 degree); 4. a mig welder (get an auto-darkening welding hood, if you've ever welded without one you never will go back); 5. Cleico fasteners and cleico pliers(if you haven't heard of these check an aircraft tool place or Eastwood if you want to pay more; 6. a variety of hammers; infinate patience and body panels and doors that have been completed far enough to dry fit, so you may properly fit the sills and rockers. Some say the engine and transmission need to be in the car for a proper fit, due to slight frame changes that will occur from their weight, but I did not find this to be so. Then grind off as much of the welds that hold the parts you want to replace as far as you can. Floor pans easy, rockers not too bad, sills just keep working and don't be afraid to cut out chunks of the sills) to make it easier. You are not going to reuse anything you cut out. Of course you do want to protect the parts that stay in place, but light damage to them can be easily welded. The hardest part for me was fitting the new sills to the front part of the foot well area. It can be done, but for a while I wasn't very happy and had long since run out of new four letter words (and I know many, many four letter words). To answer your question (too late to be brief) the only real skill is probably welding. If you have a mig or tig welder and can run a bead with it you are probably good enough. I would not recommend oxy-acetylene just because of the heat and warpage factor involved. The real time consuming part is fitting the new pieces. They have to be clecoed or tack welded in place and then you have to check the fit of the body panels and most importantly the door. Minor misfits can be changed later, but you don't want to have to undo any of your major work to fix something you could have avoided. Fitting doors is hard enough if you just remove one and reinstall it. Mark the hinges once you get them fit. I think an average mechanic can do it, you just have to be willing to take your time. Get help if it is available, from someone who has actually done this to a Healey. Don't attempt this an a tight garage next to your non-Healey automobile. I came close to burning down the barn a couple of times despite being a fairly careful fella. Lots of sparks from grinding and welding. I'm not done with the project yet, but I've driven it and am doing the final dry fit before I paint it (yeah I'm doing that too. It's a sickness I have relating to being too stingy to pay anyone for something I think I can do. At least my wife made me see the light about replacing the roof on our house this summer. We hired that out and I had more time to work on the Healey.). Good luck, Hope this helps.