I have a 2007 ML320CDI with P3/Airmatic. It has been an incredibly reliable vehicle. I did blow out a rear airbag while towing a dump trailer and I was able to replace those (both sides) for about $370 after help from the forum (yay forum)

The new rear airbags were about 1.5" higher than the old ones, but otherwise I noticed no real difference.

My ride quality has gradually degraded over the 100k miles. I feel the rear end wants to skip a bit more over big bumps than when the vehicle was new (despite Airmatic repair and it continuing to function normally)

Should I be looking at replacing the conventional part of the suspension now that I've passed 7 years and 100k miles?