I'll probably get panned for this, like i did years ago, but my smart now has over 208K miles on it, so i must be doing something right. I change the oil every 5000 miles, do all my own servicing, and drive it like i stole it.
IMHO, the WORST thing you can do is baby it. The factory transmission programming lugs the engine something terrible. Don't be afraid to rev it up, and blow it out regularly. Even at 208k miles, i regularly run mine up to redline. Never had to break open a seal on the engine. You lug it, and you will burn exhaust valves.
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