All I can say is good luck.
My expectation you will be very disappointed after spending the $ to swap it over to aluminum welding just to find out that the machine/welds are not able to reliably meet your needs. If you want a consistently good weld with a low machine cost tig welding has the advantage over mig welding. (The cost of Mig welding with this welder is not worth the investment. You need a spool gun that pulls the wire out not pushes the wire out. If you use this welder with soft AL wire, it will make a birds nest in the unit. The best way to mig weld with Al you will need a new lead with a pull drive in the head of the gun. It is NOT worth upgrading this welder! Yes they have the adapter to be able to weld AL with this welder but please do your research before you put any thing into this welder.) If you are welding anything 1/8" or under you will be more pleased with a tig welder because you will be able to control your temp, looks better and it will produce the clean and strong weld without porosity! For example look at this welder,
http://www.millerwelds.com/products/...p?model=M00337
Best of luck.