I'm dealing with mine right now as well, seeing you have airbags in the front i believe you are also in the same club as me with having the joyous 4-corner air suspension!

I would say take a bottle of soapy water and spray the struts down while the compressor is pumping them up, just to see if you can see bubbles which would indicate a leak. my car is in the shop now, probably going to get a call tomorrow and they will tell me both fronts are leaking.

both my front sides would slam down overnight, the right side more than the left, and yes i say get the whole rebuilt assembly from arnott if you are going to replace, its only 50 bucks more! there are DIY's on their website and if you are mechanically inclined it would be worth it, but for 1300 and a guarantee on the work performed i would say thats not bad at all!