96 rmw hitch , springs etc...!!!

Hello everyone, just picked up a 96 buick roadmaster wagon. Equipped with the tow package. I have a few questions regarding towing.
1) where can i find a class 3 hitch?
2) id like to lower the wagon, if i go that route what can i do to keep the ride height with my race trailer??
3) where is the onboard compressor?!!

The onboard compressor is behind the front bumper cover, at the left, behind the wheelhouse extension.

To keep the ride height, you can either use the original style air shocks, or non air shocks and airbags inside the springs. You will have to put a small piece of exhaust pipe on the top spring mounts to keep the springs from falling out when changing tires/jacking the car. This might cause issues with the airbags, so you would probably be better off using air shocks. The sensor at the rear axle can be modified to the height of the car with a different length/shape rod between the axle and body. There are a number of companies that make springs.

Class III hitches are no longer made, except for custom units. You may be able to find one on a junk yard wagon.

Try: http://kds-performance.com/91-96-hitch-assembly-and-hardware-kit/

I messaged kds performance and they still make class 3 hitchs! And they are local to me.

For the rear suspension is there a link to see how to adjust the sensor for the rear air shocks?

There is no link that I know of. There is a ball and socket joint on each end, with a threaded shaft between them. Depending on the new ride height, you may be able to insert a shorter shaft, or make a bracket to produce the desired distance between the axle and sensor. It does require a totally flexible ball joint on both ends to compensate for all possible axle movements.

has anyone bought this KDS hitch? any comments on the quality, installation, etc ?