Hello, I'm Chris. Thanks for visiting Just Answer.
I assume you have electronic suspension. If that's the case then I would just replace the shocks using Monroe sense trac.
HD as in a brand or HD as in heavy duty?
Being that its 13 years old almost any brand of shock is going to help.
Shocks last about 60k then they start showing signs of weakness. Then around 90k you start seeing ride performance inappreciable.
Bilstein is a good brand.