Just a little FYI on DOT 3,4, 4 plus, and DOT 5. Each one has a different boiling point, obiously DOT 5 is the highest. MBs call for DOT 4. The Polo being a VW probably calls for that as well. Most of our domestic cars here in the states call for DOT 3.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section