I just put the 3" ome 881 coil lift w/ aal on my '99 std cab 2.7l. I hear people saying these coils will sag over time. I know all springs will sag over time. Will they start to sag quickly or what? How will i know if it's the springs and not the shocks that are bad. How long will they last if it's just used for mostly highway driving? right now i think the lift is great. rides nice on the highway too.