They just openned an offroad 1:10 track in my area. Mostly for Slash class, but that'll be causing some ST's to come out of closets for SURE.
F150, I'd run it a few races before grabbing upgrades. You may find that the truck is ill suited to the track, or to the competition. Instead of shocks you may be looking for a roller.
OR... Your current shocks may be perfect for it.
Depends alot on the track layout, and size, and material.
Just rebuild what you have, make 'em fresh and start there. Try a different oil/piston mix before you go replacing shocks. You can probably adjust what you have.