Yes, we're in the Ultra Low Sulfer Diesel (ULSD) phase. ULSD MUST be used with the new '07 diesel engines with the new particulate filter systems. ULSD can be used with all other engines.
I believe what jk_and_dog is referring to is that Winnebago is out of the 36' 2006 chassis without the emissions equipment, which adds $5-10K in the price of the engine, and therefore must go with a 2007 chassis at the higher $$.
I am not surprised they are gone by now.
jk -- can you give us an idea how much the new engine/chassis drove up the price?
'07 Winnebago Journey 34H - CAT C7, Koni's, MCU's, SS Bell Crank, Safe-T-Plus
'07 HHR Toad, SMI AFO, Blue OX