I use the additive only for noise reduction. I cannot get comfortable listening to what sounds like ball bearing balls banging around inside the combustion chamber and find the less than $1.00 it costs me, when I am having the problem, well worth it. I don't always use an additive, which means a bottle of RedLine will last me more than several months. The added cost is trivial and the peace of mind is highly valued. For me, it doesn't get any more technically complicated. I spend very little time looking for smoke that normally doesn't exit from my 1998 E300 TurboDiesel, or my 1983 240D, to see if the additive had any effect. It is all about being able to hear the regularity of the Diesel engine noise while driving and know all is well. Jim

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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)