WJM,
No, I don't have a template. I should make one, huh. Note that each car is slightly different and you'd need to modify the plate slightly to make it fit properly, as well as drill different mounting holes for each brand/model of speaker. I had to make new plates for my MB Quarts, the Infinity plates would not work (hole too big & shaped wrong).
About the Jehnert setup. There is one small photo in the installation guide that shows the mid/tweeter setup. You need to look carefully for it in here:
http://www.meimann.com/docs/mercedes/Jehnert_W124.pdf
The full W124 sedan setup includes both doorboards & grilles (in your interior color), four MB Quart 6.5in woofers, two MB Quart 4in mids, two German-made soft dome tweeters, external crossover, and instructions. Price with shipping is about $770 EUR, or $875-$900 USD (depending on exchange rates). That sounds high until you realize that having a stereo shop custom make door panels would cost at LEAST $500 (to have it done right), and then you would need to buy all the speakers. The Jehnert setup is already designed & engineered to work in the 124. When I get the kit, I'll take some good digital photos & post them to my website. Remind me in a few weeks if I forget...
