First, come to terms with your 95 S600. It's ALREADY killed you.

With that out of the way, you can elect to keep it alive as a hobby car, or junk it like everyone else.

Your motor actually has 3 ignitiion controllers - the 3rd is a small "contention" unit that is supposed to resolve differences between the two 3L six cyl motors that make up your 120. More than often, your problem results in misfires across the sequence, and will ruin the motor. Results are usually a hole in a piston, bent conrod, busted valve etc. Most 120's have died this way.

If you elect for option #1, then go get TWO units from the junkyard, try Potomac. They may or may not have them - this is a common problem with 120s.

I saw a lady have a real heart attack one day about 4 years ago when she was given the repair bill over one of these - I think it was about $21k or so. Ambulance came and everything. She had purchased the car for "a steal", and proudly rode it around for about a month. After her son had put $5k ghetto wheels on it too