Hey Ragoodsp!!!
This discussion has become far too technical for me, but I'm enjoying the hell out of all the comments! I guess that's one of the benefits of this forum!!
For clarification, I just received my sprinter in Feb -- the date of manufacture is Nov. 2011. the date on the tires indicates the 28th week of 2011, so I don't think it is one of the 2008 chassis Stuart & Kermit bought in the sale.
Since I've only had the PC for a couple of months, and am waiting for the new sofa bed, we've only taken one trip to visit friends & plan a trip to Newfoundland this summer -- from MD to below Macon, GA - about 1500 miles (I think 1477 actually, with a few additional to the local station to top off the fuel). I didn't notice any exceptional noise in the cab at any particular speed (65-75 or other), in fact, much quieter than the 2006, 2350. There is insulation under the hood, and though I didn't check the firewall, there is no where near the heat from the floor. there was in either the 2350 or 2552. Most of the trip was on interstates, and 2 days each way -- 4 tank fills, yielding 14.3, 16.4, 16.8, & 17.6 mpg, for an average of 16.3. I'm hoping this will improve since the 17 figure was the last tank, and to be honest, I was driving 55-60 instead of 70.
I hope this helps -- I will try to post this on Ron's thread, but it's so "young" it may not be a good representation. I will be going to Elkhart when PC gets the new sofa, and will have more data.
Best,
Jack