Guys If you have the 08 (I know its not listed as covered in the TSB) Go ahead and ask your dealer to do it for you if you want it.
My dealer did it for me No issues. He was pretty surprised that Toyota is still building these trucks with the old springs.
I wonder how many times Toyota is willing to lose any profit made on these trucks before they decide to build them with the new springs and shocks in the first place? My guess is that a very small percentage of users ask for it.
They are charging Toyota around 1500.00 for this work I wonder what Toyota makes in profit per truck.
BTW It rides nice with the TSB Stiffer for sure but still nice. Not much sag at all with my neighbors riding snow blower loaded up.
Ill test it this weekend with all my duck hunting crap and 3 guy in the back seat on some nasty terrain, - Pre TSB it would bottom out.