Well I'm not Italian, but my brother of another mother, is and I'll ask him tonight. (And btw, Italian mothers make the best cookies and cakes.)
Porsche is ALWAYS 'Porch-shé' as others have mentioned, Brits also called it so. Only North Americans as far as I know, say 'Porsch'
Heckler und Koch is 'heck-ler' 'oon' 'koc'
Das Boot is not 'the boot' but rather is 'the boat' and pronounce ...'das boat'
As for cooks, try your hand at pronouncing Köche. Hehe it always seems to make people make a goldfish mouth look.