Depending on your driving style, the decreased cross-ven tilation to your rotors could cause excessive heat, leaving you with warped rotors or brake pad glazing. However, if braking duties are kept to a moderate level you may be fine. Although a few of the cars I've purchased in the past have had them, I immediately removed them and experienced the joy of cool brakes (temp) and grimy wheels.

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2008 GL320CDI 6K
1970 280SL 112K
1982 240D 210K (Sold)
1973 220D 220K (Sold)
1967 200D 160K (Sold)
1992 400E 139K (Sold)
1988 300E 148K (Sold)
1987 300D 257K (Sold)
1991 300E 108K (Sold)
1987 300E 131K (Sold)
1978 300D TMU (Sold)
1980 300D TMU (Sold)
MBCA Member