Knock - sound anything like heatshield rattling?
 

Hey, I've been hearing the sound of a heathshield rattling for a bit (bipes, 14 pulls to 10, 80/20 meth injection, 5psi, stock exhaust + Greddy DP)

My question to those who've heard knock before is; does the sound of knock sound enough like heatshield rattling to confuse the two?

more like rattling a can of marbles with a lining of cotton.

like if you had a coffee can loosely filled with nails and you tapped your fingers on the side. Thats sort of what it sounds like.

If you've never ever heard it before its really tough to distinguish it from other things. But once you know what to actually listen for, you'll be able to spot it in lots of cars including your own.

So it would probably be a little more metallic than what I'm hearing, because this rattling happens on the highway while cruising at certain RPMs, but I take it ping would be much more likely to happen at full throttle/boost only.

Yes, if it were actually happening at cruise, you'd be hearing it pretty much all the time.