I have never seen a timing chain break in any of the v6 engines, only the dohc 4cyl. What I have seen as jporter mentioned is broken cams and dropped valves. Last one I disassembled dropped a valve into the cylinder and u can imagine what happened after that. U may not be getting scammed but u are definitely dealing with an uneducated service advisor. If a timing chain let go in the car there would be no engine damage. U would line everything back up, put in a new chain and tensioner and go on about your way. Most of the time with these engines there is at least a rattle, clicking, or strange noise from the engine before they let go. As far as pricing for the used engine, including the 500 for the timing chain job and a 12/12 warranty for $2300 isn't that bad. I know the place we use for motors charges extra to warranty the engine. Just make sure the warranty covers parts and labor. Some only cover the engine itself not the labor rate to put it in. Also if u really plan on keeping the car check into a re manufactured engine. We have had some luck with the Jasper's that I have installed in the past. Just see the price difference. It may be worth it.