I learnt how to pronounce Porsche the same way as Jeremy Clarkson did in Top Gear but that made me an Alien among my friends (Don't act angmoh/act atas la). As Porsche originated from Germany, the Germans pronounce it as Por-sha, British and Americans mainly Porsche as it is and local (Singaporeans) say Por-Shayyy.
And I just realized I've been pronouncing Volkswagen wrongly my whole life.
"Volkswagen: We said earlier that Germans turn their 'w's into 'v's. Well, their 'v's also become 'f's. What the eff, right? So the biggest German carmaker is folks-va-gun, with that last syllable a clipped enunciation of "gun" (as in pistol). If you're keen to get a job with the new local distributor, get the name right: folks-va-gun."
Pagani Huayra - Jeremy Clarkson & co has stumbled over the Huayra many times and hates it.
According to Horatio Pagani himself, it's "why-air-ra".
Latio - For me it's La-Sio instead of La-Tio
Audi - It should be Ow-Dee, not Aw-Dee
Other commonly mispronounced names:
Peugeot
Tuscani
Hyundai
Volkswagen Touareg
Nissan Qashqai
Renault
Citroën
Koenigsegg