I swapped out the air springs for coils and had ZERO regrets. I liked the air springs but grew tired of having them go out at the worst possible times every year. I certainly didn't miss the sagging tail on the '03.
The stealership told me on numerous occasions that the compressor was "bad", yet it was working perfectly even after I did the swap. Factory coils and insulators, then T'd off the air line and left everything else in place.
Somewhere in parts heaven someone will reap benefits of new coils and all the other stuff I dumped into that beast before she was totalled.
