1999 2500 van conversion ball joints

We have a '99 van conevrsion all decked out as a mini-motorhome with 32,000 miles on it. Its built on a Ram Van 3500 chassis and it weighs in at just over 9000 pounds. So the load on the suspension, wheels etc. is at the higher end for the chassis - all the time. Lately I've heard a clunk from the front suspension when applying the brakes while backing up. Since I've experienced worn ball joints before, I thought I'd check them out. There is a little movement in the top ball joints when you rock the front wheel holding top and bottom with the front jacked up. My Hanes book says any movement indicates worn joints and they should be replaced. I've done this before on a Chevy pickup and the Dodge looks very similar.
My question is, that if I only got 32,000 miles on the OEM ball joints, is there a better grade of replacements I can get. I'd rather spend extra money now if I could get longer life from the replacements. Are there any suspension mechanics out there who have experience with a better grade or brand of replacement parts? How about grease? I've been using molybdenum disulfide chassis grease and I lube it myself since the lube places I've used don't seem like to do a thorough job. Is there a grease that will extend the life of suspension parts under higher load conditions?

i believe the dealer ball joints are the better ones and go the longest on these and mostly all dodge and chrysler vehicles we did try all these aftermarket lifetime warranty ball joints and other front end components and dealer ones go the longest and for the grease i would try synthetic might be worth a try

Couldn't recommend anything - but I've been through a couple sets of ball-joints on my Ram 3500 (15-passenger). At least one was a faulty part. Didn't even last a year. Maybe there was a bad batch from the manufacturer?

Is this clunk only when the steering is turned all the way to one side ? You may have to grease the steering stops .