[..P]

It does sound like injector noise, but it also sounds like the normal sounds of a double overhead cam engine with 4-valves per cylinder. There are a LOT of moving parts, and hearing a faint ticking noise is probably the sound of a healthy engine.

I agree that most of the ticking is probably coming from the injectors. In order to isolate the "tempo" and the actual frequency of this noise you're hearing, you could take a long handle screw driver, and put your thumb over the end of the handle, and put your ear to your thumb. Then probe around near the injector, you should be able to understand exactly what an injector sounds like. Better yet, get a mechanics stethascope. If you use the screw driver technique, take all due precaution to stay out of the rotating machinery, including the electric aux fan, and stay away from the high tension wires.

My main concern would be evidence that the timing belt had been changed within recent months and milage.

regars, P