Further question:
While I was able to loosen the left side lugs with the 1" impact and my small pancake compressor, I was unsuccessful on the right side. So now I'm thinking of getting another compressor with more 'oomph' rather than paying a shop to do it.
How much difference would using either 150psi or 200psi make in the amount of torque output in the 1" impact? I'm looking at a couple of used compressors on Craigslist with those outputs. Both compressors have tanks int he 15 gallon range so there will be more air to power the wrench.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13