the burner itself is half the BTU equation. the regulator output PSI is the other half.
My KAB5 comes at 155,000 BTU with the 15 psi regulator (I believe). I could put a 20psi regulator on it and dish out 225,000 btu's if I wanted to melt the paint off every house in the neighborhood.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10