jt,

Downshifting is good for control when you do it right and should not adversely affect the rest of the car in any way. If you are coming to a stop, it is likely easier on the clutch to use the brakes though, and since you have no use for the extra power available at the higher rpm after you downshift when you are coming to a stop, it makes more sense to use the brakes.

You will likely get a number of responses to this question, but engine noise, unless there is a loud and not healthy sounding metallic clanking, is not unusual. Most of the normal noise is really exhaust system noise in most cases, and it gets very loud veryt quickly as the engine speed increases. Not much you can do about it, so most of us just accept the noise and drive on.

My daughter drives our 1982 240D very hard, at high rpm (she virtually redlines before shifting in every gear), and the car runs extremely well. It has 311,000 miles now, and she drove it back and forth across the country last summer. It starts in 20*F weather without any hesitation or plug in water heater help, etc. So, downshift when you need the extra power or control, and take care not to slip the clutch or use the clutch as a brake - they cost a lot more to repair/replace than brake pads - and the car will probably be rejuvenated.

Good luck, and next time a kid bites your finger give him a squirt of Tabasco sauce or something. They are like puppies and need to be taught to connect bad behaviour with bad experiences.

Jim

__________________
Own:
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

Owned:
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)