Greetings!

Below is a picture of my beloved Victoria, a 1991 300E 3.0 liter M103. As the poorly positioned badge implies, she has been through a fair amount in her life.
From the drilled in cup holders with plastic Mercedes emblems and the aftermarket shift knob, to the OVP relay held in by wire similar to the kind used to hold in a loaf of bread, you can tell that a DIYer had their hand in maintaining this car.
This car has a ton of gremlins that I'm working to address, and would appreciate any and all input. I'm a DIYer as well, but I like to do things the right way.

Context: It has 90k on the clock and sat for a year or longer prior to my mechanic purchasing it from an estate. It had practically brand new tires, brakes, spark plug wires, distributor cap (assuming rotor), and really clean transmission fluid. He sold it to me as it wasn't in BAT condition, but had enough life left in it to keep on the road. I have owned the car for several months and have fallen in love. Given the car market, I can justify spending just about anything over time so long as I don't have a car payment.

Here are the issues,
Symptomatic:

• Slightly rough idle (Prior to EHA replacement the idle felt like a misfire, now it holds more consistently)
• Unpredictable cold start (sputters then will idle at 1200 or 600 and anywhere in between, no warm start issues)
• Subtle hesitation in lower range of RPMs <3000 when cold

Specific:

• Melted fuses (D, aux fan is always on, 7, just replaced blower motor and fuse melted a few hundred miles later)
• Several pinholes in the muffler
• Driver seat motor is out (seemed like there was moisture in the cabin from sitting in a field)
• Subtle blow-by
• Cracked pulley
• Slightly worn belts
• Randomly drains the battery (has alarm system, know that killed the battery one of the times)
• Antenna randomly will be extended after hours of the car being off (replaced the deck, and the antenna is currently unplugged)
• Faded clear coat spots, dings and dents, cracked grille spots, general wear

Work done:

• Several oil changes due to sitting
• EHA valve replacement (was leaking, improved idle and responsiveness)
• Cleaned ICV valve
• Replaced blower motor
• Checked OVP relay (was held in by wire as mentioned, prongs don't directly match receiver, MB part with paint pen on it, single fuse style)
• Replaced battery
• Changed brake fluid
• Repaired monowiper
• Replaced spark plugs
• Replaced air filter

My concerns, analysis, and next steps:

• The subtle blow-by and sputtered cold start may suggest a problem with the rings (will get compression test)
• KE-Jetronic system may need addressing/new injectors
• Distributor cap and ignition rotor are in the mail as of 6/21/22
• Check fuel filter condition (may have been replaced by mechanic)
• Potential OVP replacement
• Source driver seat motor from junkyard
• Check O2 sensor condition
• Clean/replace additional sensors (would really appreciate guidance on types and locations)
• Valve adjustment?
• I am not handy with electrical, so I will probably bring it to an electrical shop in the future