they just wont disclose it to the buyer of the car Im sure, "oh by the way, your awesome new 5.0 has no warranty coverage" smh. OP this is by no means a shot at you, I just know dealerships all to well
I came across a used 2011 with like 5k miles that looked great on auto trader...When I showed up to look at it I saw aftermaket AB's and a short throw on it that felt like garbage when I ran through the gears with the clutch in. Then when I popped the hood it was clear that the stock intake was removed and put back in...Im not talkin small scrates and rounded edges on bolts...the entire face of the strut mount area must have been so mauled that it was clobbered with touchup paint, and whoever did it did not do a good job at all.
I asked the sales guy how he got the car. His responce was, "Some guy came in and traded it for a 2012 model..." Me, "So let me get this straight..someone came in with this car, and left with the same car a year newer?" Sales guy, "Yes." Me, "Good luck."
This is the reson why I stopped looking for a used one...

