I've never really looked at air tools at sears, but I got my ingersol impact at Home Depot or Lowes a while back. It was $115 on sale, probably find one cheaper now though. The impact is rated for something like 350ft/lb in reverse. What you actually get depends on how high your pressure is and how much flow you're getting. I run mine all the time on a 20 gallon/3hp 'magnaforce' compressor that I don't think gets over 90 psi and it works fine. I still would give the lugs a good soak with blaster, then the breaker bar/pipe treatment. If that doesn't work warm them up a little with a torch, just the nut, since you'll be replacing them anyway. As far at it 'not being worth buying another tool'... since when does it have to be 'worth it' to get another tool? I think it's worth it to not pay someone $30 to replace your nuts.