From personal experience, an aftermarket ext. warranty saved me lots of money on my last vehicle -- '99 Chevy Venture minivan. The warranty cost $1000. Had 2 bad coil packs -- $500 for that. It paid for an AC problem -- $300. Also it paid to replace the manifold gasket (known problem with that 3.4 V6 GM problem -- GM should have issued a recall or at least paid for half the cost for all the owners who have that engine). The gasket problem was $600. Also, the warranty paid for like $300 of assorted other problems. I sold the Venture at 85K miles and the new owner paid a $50 fee to get the warranty transferred, and at 98K miles (right before warranty ended), the warranty paid $700 for some tranny work. So the warranty saved me $700 and saved the new owner $700. I am surprised that the warranty co's aren't charging more for their policies for cars that aren't very bulletproof, like the GM
3.1/3.4 V6 powered cars, for instance. Also, a thing to watch for is that the warranty only covers the actual bad part, so if the shop opens up the engine, the warranty will only pay for the bad part(s). So you may want to tell the service writer to have other cheap parts replaced while the engine is apart (and you'll pay extra). Because most of the cost of the repair job is getting the engine/tranny opened up in the first place.