I'm having no popping or squeaking at all after doing the install just before the trip I'm currently on. I did not add washers as some have mentioned to "fix" the gap problem -- though that seemed like a smarter fix than I elected to fix the gap issue. I did, however, crimp the hanger to minimize the gap as opposed to filling the space with washers.
I did add more lock-tite and lube than was provided by Hellwig based on input from others.
I'm writing this from Yellowstone about 1000 miles from home. We had 40 knot crosswinds across the Mojave Desert. Though we got rocked, it was a FAR better ride than in the same conditions before. I didn't get nearly the "dirty air" rock from trucks I experienced before, either. Cornering has improved significantly
But, thankfully, "no popping or squeaking".
I know this is a stupid question, but has anyone actually asked Hellwig what they attribute the noise to? Well all have pretty much the same vehicle and I'm assuming the actual sway bar and hardware used in installation is pretty much "cookie-cutter". The popping issue seem to stem from how their product is installed. I think Hellwig should/does have the answer to the $175 question! (They just need to put it in the installation instructions!