Well I know the 60 gallon 2 stage Belaire and HF both use the T29s IMC/ABAC compressor pump.
The 80 gallons ones used the B6000 pump.. HOWEVER it looks like the 80 gallon is no longer available from HF.
HF parts breakdown (For both models) http://manuals.harborfreight.com/man...3999/93274.pdf
Website.. You'll find the pumps on the LH side. With parts breakdowns.
As I said, there is no real warranty from HF unless you pay for it. I'm sure it's not the case with Belaire.
however I'd be a little upset if I knew they knew they used the same pumps but denied it to try to justify their $1000+ price difference.