How I spent money
Hahah well that's true it is a want but... Well what direction do you want to see me go with the car?
Well the US spec 380SEC for '82 ad '83 was an awful slug, it only puts out a miserable 155 hp ..
I would dump it entirely and buy a newer euro spec 500 engine or if you can find one and afford one, get a 300 hp ECE spec 560 euro. I am putting one mine real in soon!!!
The 500 engine is the best bang for the buck I think, then mate it to a good 2.65 or a 2.82 LSD for lots of low end grunt (though be careful especially in rain, they are tail happy cars and can really wash out on you if you get too frisky at low speed or starting out.. don't ask me how I know it)
Put in a first gear start module; though they are not in business now, Bergwerks made the best ones for these cars and look for a used one;
H & R or eibachs are best mated with Bilsteins, HD or comforts. In 15+ years with both of them, I have noticed no appreciable difference between them in emergency, cruising or canyon carving ability or comfort, the only difference is the amount of rebound in them and it is slight, so either would work well..
I bought a Remus box that I was lucky to find but it was very very expensive. You could look into Timevalve, Borla or Eisenmann for this car.
These cars are really meant to be long distance high speed cruisers, though, not hot rods.
They are at their best gobbling up huge amounts of macadam at a stretch.
They were engineered to cruise all day at their top speed, which for the 560 engine was 149 mph.
IF you can find any and afford them, AMG springs are good, though I have eibachs, along with AMG tri-Y headers and downpipes; I got a pair and absolutely love them.
If you are in a stazte like Michigan that allows it, run the car without cats/precats. A GREAT way to gain power.
Keep all fluids fresh, good NGK plugs, and cosmetics good.
Go for bigger 16" or 17" wheels (I like AMG Pentas) or nice W140 replica ASA wheels from tire rack, I am running 225x50x 16 for 15 years and it s just right.
(I don't care for staggered wheels).
ATE or Mercedes Benz rotors are just fine.
Top it all off with a good W126 skid plate to protect your lowered car.
And of course, buy euro headlights. Do that first.
That is how to spend your money to best effect. Fancy body kits and stereos to me are a waste of time and money though a decent sound system just needs good speakers, maybe subs and tweeters and a good amp and a $150 player and you are there.
Here's a peek at what I did (above) and what it looks like.