Use the expensive stuff, the windshield is part of the body strength on later cars, and the cheap adhesive is likely to be black and sticky rather than the high strength stuff MB requires.

It will also allow the windshield to slip around and leak, BTDT on my old Dodge Aries.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!