Last month I bought an HFT 1/2 240 ft lb electric impact wrench for $38. Works great. At first I did not like it b/c I could not get a hub nut off then I remembered I put it on with a breaker bar with a pipe over the end that I then stood on, which I weigh 220lbs. They also have a battery powered version impact think is around 330 ft lbs.
1/2 in. Electric Impact Wrench