The Jato tires are made more for on-road then they are made for off-road. You dont need a spoiler that just helps, lowering the vehicle is not that hard it just onvolves taking the shocks apart and taking some fuel tubing and cutting them to the lengths needed and place them on the shock shaft. For firmer suspension just get new spring, as for the smaller diameter tires you dont need them.

But you dont need to do any of this if you dont want to, thats just if you want it to handle a little better while traveling at speeds.