Holy Cow!

I just bought a used 99 with a 5.4L engine.

Now I'm hearing about "piston slap" and "oil leaks" and other assorted nightmares about that engine.

I'll ask just these two questions...
1. How do I determine if my engine is suffering from "piston slap"?
2. Is there any way to tell if my engine has already been replaced?

Any other advice?

Thanks!