I can't give any real feedback but I did buy the Gen IV for my 69 Camaro long ago after noting good feedback at another forum from a lot of users. I think you can trust the company and the quality of the parts, if that was any part of your query.
I only have the unit installed under my dash, and the firewall connector installed and connected at this point.
I would expect its a good buy for the Impala. Been kind of thinking of how awesome it would be to have one in my own Impala, which never came with A/C.
Don't know the difference in price but Blue Print makes their own blocks, heads cranks and rods all in competition with Scat and Eagle (all made in china) but all are brand new parts not refurbished used ones. I have seen them featured on a few TV "How to ..." shows but knowing the Chinese I will wager anything sent over here to be featured on TV will have been checked to verify everything was in spec.
I am also sure that the Chinese are honoring all of Chevy's patents and copyrights as they are sticklers for being law abiding, at least that is what their paid spokesmen (usually an attractive young female) say when you meet them in person. The lack of a license on their ads is a simple over sight due to a poor Chinese to English translation. If you believe any of this I have a bridge for you used by a little old lady who lived in Brooklyn.
Yo Dave, not sure if your mouse got away from you or what here but the Surefit system is part of VintageAir product line. I've honestly never heard a bad word about VintageAir.
"Jack Chisenhall, owner of Vintage Air was recently awarded the 2011 Robert E. Peterson Lifetime Achievement Award at the 13th Annual Hot Rod & Restoration Trade show. The Robert E. Peterson Lifetime Achievement Award is awarded to true innovators in the hot rod industry.
Jack created the whole aftermarket air conditioning market in the hot rod industry when he founded Vintage Air back in 1976. Read full story"
My Bad! I was keying upon the Gen IV part (actually it is a Mark IV vs. Gen V and Gen VI) and thought we were talking about a BBC crate motor. Ignore my rant as it has nothing to do with your problem.
As far as A/C goes I prefer adding a knee knocker evaporator and using GEn-YOU-Ine Chevy brackets pulleys hoses and a Harrison or Frigidaire if old enough compressor and condenser in the engine compartment. I much prefer the GM parts over the bolt on Sanden compressor that uses a different belt pitch (won't fit in a Chevy pulley). Sanden was used by Chrysler, and York by Ford, but GM used either a Harrison A6 or a R4 scroll compressor which is much better in design (no reciprocating piston like inside an air compressor).