Few things,

1 I have bought several cop cars from MHP and one from Renton Wa PD and they all had engine covers.

2 I have seen waaaay to many engines in these durangos break rods after getting rained on, we now recomend new intake O rings to any customer with 100,000 on their durango or if someone says it idles rough in the rain.

3 those engine covers are acoustically designed to make the engine quieter, if you put one on with the engine running it really quiets the injector and lifter noises down a lot.

4 unfortunately I can't get one from a ram to fit because they are too thick to go under the cowl and the one from a car is totally wrong because the throttle body is in the wong spot.