The stainless lines I have help a little bit, but it's not a huge difference by any means.

As to your other questions, I'm in the same boat so I await the responses too! I'll likely just do 600SL/late E500 front brakes...most economical route.

And forget trying to find used...NO ONE has any. At least in the continental US.

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo