Funny story about extended warranties....I bought one (limited time, unlimited mileage) for a Mercedes E550 as i figured it would be costly to repair if it ever required it.
It was a biturbo v8, 4matic (all wheel drive). I had it tuned very early in its life by Weistech engineering. Their specs said it was good for 540hp and 715lbs tq
Mercedes Benz AMG M278 ECU Tune E550 S550| Weistec
I put 140k miles of HARD driving on this thing (not abusive, but hard).....this thing was a beast, the only thing that I never walked away from was a v10 R8.
Anyways, my money was wasted on the extended warranty, not ONE thing ever broke on that car. I don't recall any warranty work period. Had I not bought the warranty, it probably would have blown the trans. anyways, sometimes a warranty is just piece of mind.