Just fitted Firestone air support sleeves to my 2007 Outlander. Absolutely ideal for when the rear is loaded and I am towing my caravan.
The fitting can be done without dropping the suspension arms etc., but is fiddly and took me about 5 hours in total.
Photo at:-
http://www.flickr.com/photos/the_grocer/8467636663/

 

What pressure do you use?

 

Normal running I just leave 2-5 lbs (psi) pressure to keep sleeve inflated, when loaded & towing I increase to between 15-20 lb

 

I keep mine @ 10-13psi, and full 35psi when towing.

 

Mine is 18 psi all the time. Seems fine to me.

 

I just installed the air springs on my 08 XLS to help with my new trailer (2600lbs dry weight). I am also using an eq hitch.
It is a very tight fit but I found that presoaking the springs in hot water helps to soften them. You can also remove the bolt at the bottom of the shock to help gain a little more stretch in the spring. When we had the spring installed, but it was still quite twisted, we gave it a small shot of air and it popped right into shape. Total job was about 3 hours.
I will have to experiment with the pressures using the examples you guys have given.
Thanks

Paul

 

got a part number or a link to buy the kit?

 

There you go:-

2008 Mitsubishi Outlander LS 3.0L / 182 C.I.D. Firestone Ride-Rite Suspension Load Leveling Kits

but double check as this link was for my 2008 Outlander

 

Then you need to buy a pump and controller correct? I wonder if someone makes a rubber spring booster for our car

 

No, not all all. The airsprings come with easy push in high pressure pipe that end in normal car tyre valves. Just use normal foot pump etc to pressurise.

Of course you can fit controller etc to automatically adjust from the cab, but what's the hardship in just taking a pressure reading with a tyre pressure gauge?