If yuo want to do body panels then a mig is the way to go, arc will just burn thru.
And another thumbs up for the Millar 175, I've done tons of welding with mine, from body work to bumpers, havn't had anything fail yet(knock on wood) and have yet to turn it up to its highest setting. Definatly get gas, expensive to refill but gives a WAY better result.