never ran a TIG in my life but am going to buy one and take some classes and burn some tube.My question is what size do i need.I want to use it mostly for welding .120" x 1" 1/4" DOM and .160" DOM mostly.It is for building custom bikes.The heaviest it will be needed for is welding the tube to 3/8" axle plates on the rear swing arms and hard tails.I am looking at the multi purpose machines because i could really use a plasma cutter.I am looking at this machine http://www.everlastgenerators.com/Po...05-313-pd.html there any advantage to having separate units(lot more money)I was first looking at harbor freight TIGS but they are most likely junk so i will spend more so i am not sorry later.I have been doing all my welding with a MIG and want to have cleaner,better welds than it can offer.I can run very nice mig joints but after checking out TIG welded frames it is a no brainer that they rock.Also a plasma cutter would save me massive time fabricating.