Cheers...actually have had the privilege of shaking his hand once - none of the skill rubbed off though.

With how many different engine partners have McLaren shared the Formula 1 constructors championship?

I'll go for:
Ford, Honda, Mercedes and either Renault or Porsche.....can't remember which
3 being the dominant 'marlboro mclaren'
Prettiest car to grace the tracks in my eyes.....and im a ferrari fan!
so 4?

Yep well done (it was Porsche):

Ford (1974)
Porsche (1984,85)
Honda (1988-1991)
Mercedes (1998)