It depends on your applications.. Mig is meant for multiple passes on thicker gauge metal (or thinner gauge with .035 or smaller wire). This would be ideal for making motor mounts, and tacking since you have a free hand, and its a faster process.. I use it at work for x-ray 1 1/2 inch pipe... Tig is meant for thinner material, single passes... This would be ideal for aluminum intercoolers, intercooler pipes, and just basically smaller stuff. I use tig welding at work to put a single root pass in to hold the following stick or mig passes... I encourage you to look more into it!. It is fun, and I couldnt imagine doing anything else for a career. You can also make a lot of money doing it if you do x-ray pipe work.... Oh and that cheap Harbor frieght has a duty cycle of 30% @ 165 amps. To weld aluminum you need a little more power like the Miller Diversion 180 duty cycle of 35% @ 125 amps

Double check all your coolant and oil lines....., before you take off and see a cloud of smoke behind you!