Those who are currently driving a SMART in the US already have a voided warranty
we get our warranty from a 3rd party insurance party (on our G&K converted cars).
I have a 700 cc turbo charged motor (my Honda Gold Wing motorcycle had a 1,000 CC motor Hee Hee Hee) and I'll tell everyone, I feel the difference between 91 and 93 octane in this car. Granted this is only my second tank, but I do feel a difference (even with the AC at full blast) now weather I get more miles out of this tank remains to be seen (@110 miles the indicator still shows a FULL tank, and from what I have read this is normal). I would suggest we all wait till the new 451s hit the EU market (and are tested ) before it is speculated what can and can not ignored in the OEMs recommendations.
just a thought