Some friendly advice, either get an owners manual for this car or read the one you have. All of the answers to your questions are in the Technical Data section. If you need one I have a spare 1998 W202 owners manual. Send me a PM.
Also, read this thread, especially post #9,
http://www.peachparts.com/shopforum/showthread.php?t=142384
(BTW, I use the BERU plugs in mine)
Good Luck, Dan