Put trap doors in the floorpans and when you want to go faster have everyone open the trapdoors,stick their legs out and run to push your diesel faster (like Fred Flintstone)!
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Actually, you'll get the best performance by setting everything to factory spec. (valve adj., turbo adj., new air cleaner, make sure the intake/exhaust manifolds are tight and don't leak, check the timing chain for stretch, do a compression/pressure test, new fuel filters, trans. adj. etc., etc.), and if everything checks OK your turbo diesel should perform better than many others on the road. The official M-B manuals and the Haynes manual will provide lots of info - both can be found on eBay. I prefer the print version over the CD for the M-B manuals. If you have problems - then do a post and you'll find a wealth of knowledge and experience here to help you.
Good Luck!
Tom