What's the symptom with it? As far as repair shops go, it's hard to find someone that'll properly diagnose the system. Most every case I've read about air suspension was filled with a ton of new parts, a hefty bill and lastly a suspension that still doesn't work as it should. If you're even remotely mechanically inclined, it's a good start to check the system for leaks. Remove the protective boot off all 4 bags and spray them with soapy water. Same for the distribution valve (and the hose connections). You'll likely find yourself with a far cheaper repair than a shop just throwing (expensive) parts at it blindly.