I was getting ready to install a new set of Tokico TM RT's with 99 tall coils... when I ended up trading the 99 springs for a set of PP lift springs.
Going from stock shocks and springs (~197k on 'em) to the new setup I only noticed a slight (better) difference at highway speeds, and equally as rough and bumpy ride on the terrible Minneapolis streets. Now.. the PP springs are known give a stiff ride, so that's probably why my old worn & the new were similarly rough feeling on the Minneapolis streets.
The person I traded with was running the traditional PP/Bilstein setup, and he swapped for the 99 springs and new Tokico TrekMaster R/T's... he said he only noticed a subtle difference in the ride after the swap.
With all that said.. I'm not sure you're going to notice a huge difference in the way the truck feels. It will probably be fairly subtle, for the better. But whether or not that difference is worth the cost of buying everything is up to you.
(Note: I'm referring to the Tokico TrekMaster R/T's, and not the factory Tokico's. The factory Tokico's may be a little softer.)
In regards to what Gerdo said... I agree I already feel that my ride looks stock. It looks really good though.. especially when you are next to a stock 4Runner.