This is your closest answer so far, but is not unique to Piquet as Senna won his 3 WDC's with a V6, V10 and V12 engine.
Piquet: Won the driver's title with a *BMW, **Cosworth and Honda engines? *Only driver to win in a BMW engine out of the 3. **Only driver to win in a Cosworth engine out of the 3.
Correct, Piquet is the only driver to have won all 3 of his WDC's with a different engine manufacturer each time. I didn't put Senna as a choice as then Prost/Lauda could have been the odd one out as both Senna & Piquet won each of their 3 WDC's with different engine configurations which wasn't the answer I was looking for. Piquet I beleive is unique with the stat I chose. Could have put pictures up of every 3x+ WDC, but couldn't be arsed!
Mike Hawthorn: please log in to view this image José Froilán González: please log in to view this image Helmut Marko: please log in to view this image Jacky Ickx: please log in to view this image
I think its Le Mans related in that one of them (not Marko or Ickx) is the only one not to have won it? I'll go Hawthorn as he is considered by some (not me) to be responsbible for the 55 accident.
*Nope not what I'm looking for. **No they both won the Le Mans 24hr, 6 times for Ickx to be close: 69,75,76,77,81,82
I reckon there is one member on this forum who would know this answer with ease. It's clear as day IMO.