[N5GKP]

That's good, the injectors can be somewhat of a pain on these engines.
If the High pressure fuel pump has been replaced too that's even better news but failures of these aren't as common as injectors.

With the clicking noise, whilst it's on idle/tickover you'll hear the injectors clicking away, but when you rev it up you should notice that sound stops or goes much quieter.

Other than that I can't think of many things to say keep an eye out for - rocker cover leaks, leaks between the oil filter housing, the normal bits and bobs.