Realizing this thread has morphed quite a bit, but just in case the OP is still looking, there is a pair of Buell Stombos on Ebay for $150. I installed used Buells (from an ambulance!!) on my boat. Sounded like a large ship. Plenty loud and manly enough for the job. Also, small (1 gallon) pressure tanks, hosing and valves are all easily available on Ebay for a small price. Kahlenburgs are more expensive but the Buells look good, are well-made and are certainly up to the job!!