Where to buy Ignition Cylinder setup.
 

I need an ignition cylinder with keys and matching cylinders for my doors and trunk for a 88 420sel. Can anyone recommend a place where I can purchase these? Thanks.

Your dealer, can order, that is pretty radical unless you lost your keys. All those items can be ordered individually but usually just a replacement with the same pattern as your VIN on record.

After my only key broke off in the ignition, all that I have left is a partial key and an ignition that needs to be replaced. I figured if I were to replace the ignition cylinder they may have an option to replace it with the same key as the door locks.

I'm not sure if your car is like mine, but in order to replace the ignition tumbler, you're going to need to get it out. Unless you can turn the key to the second position to insert the tool in the holes, you're going to have great difficulty removing the ignition tumbler. Maybe it would make sense to try to get the broken key out and just order a new one from your local dealer in the mean time.

may get a key with the cylinder
 

RC,

You can order the ignition cylinder from the dealer with your VIN and registration. They will match it to the original. It is not that much more than just a key if I remember. And you get a new key with it. Call you dealer to check.

Chuck