How was the frame and cab on the 99-04 trucks compared to the 05-07 and 08-10 trucks. Do the cabs have any better sound proofing, better AC design, more comfortable design. Im wanting to do a cummins swap so looking at which generation truck i should start with. Looking to get a manual truck to start with as ill be using a manual trans in the swap. Trucks newer that 04 are really hard to find in a manual trans is the extra frame reinforcement worth waiting for to find a good deal on. I can always swap the newer suspention on the older truck if the cabs arnt much different.