Rebuilding the calipers is limited to replacing the rubber seals and some light cleaning of any loose crud. Anything more and you need new calipers. The rubber seal in question is the one between the piston and the bore in the caliper. If there is any pitting or scoring, or other signs of corrosion, the caliper is done. Trying to fix it will make the car unsafe and the brakes stick worse than they seem to be doing today. Some of this can be prevented by flushing the brake fluid out every other Spring as outlined in the manual.
As for an exhaust system, I replaced mine with a unit from Timevalve (www.timevalve.com
) which is solid stainless steel, and came with a lifetime warranty. All I can say is the system is about 12 years old and has about 140,000 miles on it. It started getting a bit loud and Timevalve did a repaired it without any documentation from me. They looked at it, agreed it was theirs and welded a seam on the resonator. Good company, good product and good guarantee.
Good luck, Jim
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)