I don't know if anything has changed for parts from 06 to 08 but I love my set-up. SAW's front and rear, 1" block and PRG uca's, rides more firm than stock but overall it is a much better quality ride than stock.
The '08/'09 Titan is no different than any other year with a PRG extended travel setup. Yes, the OEM coils are a bit longer (slightly higher in the front), but you remove those with the installation of the PRG suspension. So an '08/'09 Titan with the PRG extended travel suspension will have the same ride height and handling characteristics as an '04-'07 with the same setup.