I can't help but think there are many like me who will not upgrade right away and here's why; 2006 engines, which mine is, will require the DPF by 01/01/14 according to current CARB rules. 2006 trucks are now hitting the 500-900K mile mark, so an inframe, if not done recently, will be needed soon. I can't see sinking or having recently sunk the dollars on an inframe, shortblock, or longblock and then dropping another $10,000 plus for a DPF just to cross into Cali. Along with the negatives of roughly loosing 1/2 mpg in fuel economy, cost of cleaning/replacing the DPF's and the added risk of setting the country side on fire like what happened in WA state due to sparks from a DPF all weigh in against me upgrading for now.
Didn't I read somewhere CARB states 60% compliance on older engines so far. I think the compliance rate on '04 to '06 engines will be even less. I chose to own a pre-emission (none DPF) to avoid the headaches and added expense and plan to keep our paid off truck for another 5 yrs. This is why we have meticulously maintained it inside and out. It would be foolish for us to give up a perfectly good truck in favor of a new one just to stay in compliance with CARB, who, as Phil pointed out, comes along and decides to make our truck non-compliant, even tho at the time of purchase, this non-compliance was no where on the radar.
One can only hope CARB will ease up on the issue until a better solution comes along vs DPF's but not going to hold my breath.