To answer the OP original question, one of the best buys in air impact guns that is adequate but definitely not state of the art is the Ingersol Rand 231. This was a staple in auto and tire shops for over 20 years. Amazon has them for $99 w/ shipping. For personal use it will probably last a couple of generations. You will need at least a 10 gallon compressor at 100 psi to run it at full power to run it for at least one tire removal.