2002 Grand Marquis air ride to spring conversion?
 

Hi all. I'm working on a friend's 2002 Grand Marquis with 73k miles that runs lifted suspension (the previous owner thought it would be cool to slap 26 inch rims on it). The front is lifted by a 3 inch "knuckle". The rear has about 6 inches of lift provided by taller springs and shocks. That according to a guy in the tire shop (and although I've turned plenty of wrenches, I don't know enough about suspension to know whether that's all it has or not - we'll assume so for the moment). This vehicle comes with an air ride in the rear (it has the compressor and a yellow "air ride" light illuminated in the instrument cluster). Can anyone tell me the correct type of spring in order to get the correct stock height on the rear? I found the Raybestos 587-1137 springs on RockAuto which appear to be for stock non-air systems, will these work to get stock height on a previously bagged system? What about shocks, I was planning on buying a set of Monroe 20961s - same thing, they appear to be for a stock rear, any reason why they wouldn't work? Also, what else might I have to do to this car to make it align properly with 73k miles (by all appearances, it's probably only been run with the jacked up suspension for 10 to 15k miles) - maybe ball joints? tie rod ends?

And optionally, is there anything I can do to the air ride system to turn off the yellow light on the instrument cluster, short of opening up the IC and removing a bulb or something?

Thanks in advance!

Sometimes you can get the info you seek from a dealer parts dept then possibly cross those #s over to what ever brand you find available.