VA or Classic Custom Air

[Northern Goat]

Need to purchase an AC system for my 71 Firebird. The car is non-air with a 2003 LS1 and a Corvette accessory drive. VA says I can't use the Vette compressor. CAA says I can on their system (therefore $250 cheaper).

What are the pros and cons to each? Even if I have to go to a Sandan unit I would like to keep the compressor in the stock location. I haven't notched the subframe yet, so I don't think that is a variable.