What is the best, cost effective air compressor on the market for automobiles?

I think you'll need a upright compressor with a very large tank as air wrenches take a very large amount of air to run them. This is more of a trim carpenters size compressor.

Honestly ive got wonderful performance out of a 13 gallon campell housefield compressor i bought over 11 years ago defiantly check the capacity on each compressor you look at and for cars you are going to need larger capacity 13 gallon minimum with a high air cfm also check the reviews this is not something you want to blow up after the warrenty goes out my shop compressor is an Ingrasol Rand which is the one of the best on the market and is one of the most expensive but it makes up for it in performance and warrenty also warrenty is extreamly important in selecting a air compressor