i think it’s totally worth it. E46s tend to rust in the rocker panel area (besides other critical areas) where the clips mount to the body via green plastic inserts that are shaking and vibrating and over time they dig through paint down to bare metal and rust starts to develop. If you are lucky and yours aren’t rusted already the way can protect it. Just make sure you somehow spray it behind the clips. It will protect it from water to some extent.