Neither sentence about jet engines makes sense. The middle phrase, isolated with hyphens, is an adjective phrase that provides additional information about jet engines. If we strike it out, it becomes clear why the sentences are bad. The core of your first sentence is "In comparison, jet engines are ten times more reliable than pistons." That is a nonsensical thought because jet engines cannot be compared to pistons. The core of your second sentence is "In comparison, jet engines are ten times more reliable than those of pistons (or piston engines)." That also is nonsensical because "those" does not refer to anything. To make sense, strike out "those of": "jet engines are ten times more reliable than piston engines"

1. You’re nearly correct! I would say “ those with pistons” (or simply “piston engines”) 2. Live 8 is the name of the event—it’s being used as an adjective (“Live 8 organizer” = “the organizer of Live 8”)

I agree with the others. I think whoever wrote the original was using PISTONS to mean PISTON ENGINES.