How to tell if the engine has been bullet proofed?

I want a 2003 Ford Excusion with the PowerStroke diesel. I read that when they are in the range of 150,000-200,000 miles, that they break and require about $10,000-$12,000 in engine repairs. How can I tell just by looking at a picture? I'm currently looking online.

Added (1). I live in the North and I wanted to buy one in Florida.

Added (2). So the 7.3L is the best? What's the actual city fuel economy.

Without seeing the bills and talking to the shop who did the work assume everyone is lying when they tell you how awesome their 6.0 Powerstroke is. Navistock dropped the ball on this engine big time. High pressure oil pumps, EGR coolers, injectors… List goes on. They can go from running like a top to being a 10k pound boat anchor. I work on the all the time. The 6.7 is inhouse Ford built. The 7.3 is bulletproof in my humble opinion…

"How do I tell if the engine has been bullet proofed? "
that implies an engine has been gone through internally (externally too). And upgraded parts have been employed to perform more reliably that a stock engine.
in all cases, can't see inside an engine. So receipts are a must. Basiaclly a modified engine is only worth it's modifiacation value if all work has been documented. That means receipts! W/o those, it's considered an undocumented mod and no better than original. As anyone can *say* anything to sell a vehicle.
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generic routine periodic maint.
same goes for that. No receipts, have to assume nothing has been done. Buying a used platform w/o receipts, and one should expect to perform *all* periodic maint procedures from day one (new) to it's current point in time and milage as covered by the owner/operator manual.
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specifically,
i can't comment on projected maint costs on this platform at this mileage. Platform would need to be evaluated in person to comment on that.
and i'll leave commenting on known issues on this specific platform/power train to those who know.
i do know most diesels need a fuel delivery re-seal over time. That cost is no where near the thousands you quoted.