Do not use an impact gun. It won't work, and all you'll end up doing is breaking something (probably the impact gun).
Breaking it loose is easy. There are 2 methods that are popular:
1) Get some 1/4" or 1/2" steel plate & drill holes that match the 6 crank pulley holes. Bolt it on there & rest it against the frame on the passenger side (or the AC compressor, but be careful...maybe remove that first). Put your breaker bar on there, maybe with a 4' long piece of steel pipe to help out Y crack it loose.
2) Get a long wrench on there, one long enough to reach over to the frame under the air box. Remove the airbox & put a block of wood in place. Put the wrench on the 22mm bolt head & rest the handle on the wood block. Get in the car & try to start it. The starter should break it loose with the wrench up against the wood block, no problem.