Spot Welder VS. plug welds with a MIG

[Berg]

When I was in Highschool my old shop class had a big 220V spot welder with water cooled tips. I only got to use it on a sheet metal box I made up when I was playing around after completing an assignment. It was mounted to a stand and drew a lot of power depending on the thickness of metal but the thing made factory looking seams if you used the brake and cutter to bend panels. I was thinking of getting a similar smaller portable machine to do sheet metal work on my projects. Between my Chevelle and my old Blazer I think I can justify the expense of another welder if it saves enough time and agrivation of having to grind down welds and add dimples to keep the "factory look". I'm just worried about the access I'd have to panels that would be welded. I've been using my Lincoln 140T MIG welder and I really wish I spent the extra cash to have the fine tuning of the 140+ instead. I feel like sometimes I'd like the wire a little faster but on the next setting it is too fast. For something like plug welding would it save that much time if I were to be replacing the trunk floor and drop downs with inner and outer wheelhouses about how much time would you think it would save over drilling and filling?

[Rank]

Id put a plasma cutter high on my tool shopping list and put a spot welder down low ... with a wheel balancer! LOL