'05 Yukon XL - Rear Shock Replacement

[norcalboon]

'05 Yukon XL 2WD, 140K miles, wife DD plus used to tow 7K# TT 2-3K miles per year.

Was planning to replace all 4 OEM shocks with Bilstein 4600's - my installer mentioned that the OEM rear were more heavy duty and expressed concern about the Bilstein's holding up while towing.

Any thoughts?

 

[norcalboon]

If interested, it turns out I have Premium Smooth Ride shocks on the rear and the Bilstein 4600's are not direct replacements for hose.