Yes, I also spent pretty good amount on my car. I am lucky that I can do the most of easy work by myself to save some labor cost.

About wheel size, please make sure you complete rebuilt your suspension bushings and bearing before you change to bigger size since W107 suspension is really not made to use any bigger size. I am aware that I need to change steering dumper and control arm bushings more often than one with normal size wheels.
I have AMG 17x8 with 11 offset. If you are planning to go for 17x7.5, there are more choice of wheels with offset 20 to 22.
Please confirm the wheel disc would not contact to your brake caliper because 560SL has bigger caliper so some cannot use.
I could not install Speedline wheels when I tried.
My tires are all 215-50/17 ZR. I could go to 235, but did not want to increase road noise. Narrower tire makes less noise.

Today, when I was discussing with mu mechanic to make a special front exhaust pipe (equal length from the both banks of engine), I found out that my ABS warning lights.
I will check and clean all ABS related relays tomorrow to fix this problem.
Things like this is coming frequently since electronic parts are getting old as well.

My friends at work are also loves cars.
They have Porsche 993, targa, convertible, coupe, Audi RS4, Porsche 996 GT3, Jaguar XKR convertible and Ferrari 355 spider.
We are planning to take our car to racing circuit to drive own cars.
I know my car is very slow compare to their car, but would like to prove them how well balanced.

I hope you will enjoy SL life. Not just drive around, but also knowing well about your car.
I know they are both fun!