Heavy duty if you're carrying some heavy loads in the car. Little harsher ride from my experience, but will last longer. Comfort shocks are softer ride. More MB oriented.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k