Battery technology has changed a lot in the last 5 years. Kent use to recommend the red top Optima batteries for your older Mercedes. The problem with these batteries is they would never fit perfectly in your battery tray and in many cases you had to install a longer ground cable to reach the post.
Problem & Solution
Almost all major battery manufactures are now selling EXACT FIT AGM (absorbant glass mat) batteries that look and fit exactly like a regular battery. No modifications are needed and most match or exceed the performance of the Optima battery. Now you can have the best of both worlds. We know they are expensive but well worth it. You will realize this the first time you forget to turn your headlights off and come back in a hour !! They also do not gas off and corrode your battery posts and battery tray. And what Kent likes most in his cars is they hold a charge a lot longer when the car sits idle!
Watch the first part of Kent's video on installing batteries in newer cars where he shows and explains the differences.