My two cents:
1. Wrong engine
Don't lift the bonnet. I'd run this engine until it falls apart. If it ain't broke don't fix it. Put a supercharger on it for more power if you want.
2. Paint is ok but poor quality 6 out of 10
A good going over with a clay bar and polish will do wonders. Not very expensive especially if you do it yourself.
3. Rust free , not a spec
A real bonus! Not many can say that.
4. Wrong wheels
You have Bundt (like the baking pan) wheels. They were on 70's and 80's Mercedes. You can buy used steel wheels for about US$50 on ebay or go to a breaker's yard. You can probably sell your Bundts for about the same. Then buy new beauty rings and hubcaps, paint them body color and you have an instant upgrade.
5. No radio
If you have a radio delete panel that's actually a bonus. Some people covet them. I saw a period Becker radio online for about US$500.
6. Needs new hood, no hard top
The soft top will cost about US$800 depending on the material you choose plus installation. These don't necessarily need to be installed by a pro. If you had a hardtop you'd put it on on once, kick yourself for scraping the paint, then realize that you'd rather have the top down. It would molder in your garage until you sell the car anyway.
7. Dull chrome except bumpers are new (front not fitted)
Take them off and buff with a polisher. Just the cost of polish and maybe a US$100 bench grinder with buffing pads.
8. Dark brown interior
You can change the color of the leather with a product called Leatherique. Works great. It'll change white to black or vice versa. BTW Mercedes sells red cars with brown interiors now. I thought I wouldn't like it but it grows on you.
9. Drives nice
Super!
10. Gear linkage is like stirring a bucket of bricks
It needs some inexpensive nylon bushings. Easy fix.
11. Interior is good 7 out of 10
Leave it alone
12. Seems to sit level and drive nice
Great!
You have a wonderful car that you can enjoy right away instead of waiting months (years) until its put back to stock. Also no bills for all of that. Take it to a Mercedes event, leave the bonnet closed. People will marvel at it.
Just my 2 cents (pence).
Paul