The best replacement for air suspension is coilovers.

The best alternatives to air suspension are rated as following:
★★★★★  coilovers
★★★  hydraulics
★★★  spring suspension
★  leaf spring
★  hydropneumatic
  coil over
  coilover
  coil
  hydraulic suspension

Your alternative for air suspension is not listed? Suggest!
Speaking about air suspension, one probably shouldn't forget about pasm.

Other search terms related to air suspension and their ratings are:
★★★★★ pasm
You have in mind a companion for air suspension and it is not yet here? Propose!



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air suspension
coilovers
hydraulics