i have a makita 1/2" BTW450 18v 3A lithium cordless impact wrench. 400lbs.
it came with two batteries a charger and a contractor case for 299 shipped from amazon.
then i looked at makitas site and there was a mail in rebate for a free impact driver, the kind with the qd hex head. 3 variable speeds and it'll do 100lbs. a lot smaller than the BTW450.
check out their rebates. two for the price of one is nice.