Also, I had understood from previous posts here that HWH had a system installed for about 4K all new!
Keith, HWH did an install on my 2001 Contessa in July of 2014. I had a left rear hydraulic jack leaking bad and was told at that time non reparable.
They disconnected the jack hydraulics, capped off the lines and removed the two front jacks. The rear jacks were too much work for them so they left the rear jacks on the coach.
They installed a new compressor, rewired and re tubed the air bags to control the leveling of the coach with air only. They removed the existing control panel, and installed and modified a new control panel.
Since I arrived home I had the rear two jacks removed from the coach. The right rear I have sold along with the control pad. Still have the left rear(leaking one) and both good front jacks for sale.
The system that HWH installed took 2 1/2 days at the Moscow, Iowa factory at a cost of $4976.00! I have heard that they don't offer this upgrade anymore but can put an air system in for double the price. Not sure if that is a fact or not though!