Pat,
All of the fittings that were necessary for my installation were included with the Trim Unit kit. However, I found the instruction sheet that came with it to be about useless. There are two issues that will give the average DIY installer a problem. First you have to position the air can for the trim unit so that it clears at all times, especially the fuel tank when the coach is lowered (air bags deflated) to its lowest point (the 2000 Marquis is very low with deflated air bags), but still has ground clerance. Second, the bolts that hold the axle to the suspension cradle that are used to mount the trim unit bracket are very tight and the average DIY does not have the tools necessary for removal. I had to use the 1450 foot pound 3/4 inch impact gun that I use for tire removal to take them out. However, if you have a 3/4 inch breaker bar and a cheater pipe, possibly with a helper, that should work, but for me the impact gun was easier.
I used an air line that was located behind the electrical bay as an air source, but I think that all of the 2000 Marquis coaches have an air line in the electrical bay that will work, the air supply to the air horn relay.
If you have any further question when you start the installation just call me (713-254-4156).
Gerald