For such a competitive industry, it’s sometimes surprising to see just how much car manufacturers have collaborated over the years. Then again, the only thing more important than competition is overheads and saving money. Working together on cars, and even rebadging them, is one of the most cost-effective ways a marque can get cars in showrooms quickly when five years of development time and millions of pounds don’t fall so easily to hand. Sometimes, though, those exchanges are, politely speaking, a little shameless. We thought we’d list a few of our favourites.