I just bought a new promaster 2500 and am ready to get a new unit. I have a boxxer 421 that has cost me numerous problems . I purchased at cleansource nc and have went through many techs there and they always want to replace everything. I only have only 1800 hrs. Whats the best residential 1 wand truckmount unit to get? The 318 boxxer has been suggested. Nick Cavalier