At the beginning of summer I was ripping up the twisty's in my local mountain range when I was braking hard approaching a corner and it sounded like firecrackers coming from the transmission area.

It still does this. I've been trying to find a pattern to it and what I've found is this:

Most of the time, it happens in gear (any gear) and at high rpm (over 4K) while hard braking and it does it when at high rpm and engine braking without the pedal brake and it does it at high speeds (over 90 mph is a guarantee) out of gear and braking hard.

It sounds like either firecrackers or a two-step on a turbo car, it's really weird. The car performs like nothing's wrong, everything works as it should. I can feel a slight pulsation on my brake pedal when this happening. Nothing is dangling in the undercarriage. Lately I've noticed the clutch makes a static shock noise during normal driving every once in a while. Could a piece of something be getting bounced around inside the transmission from all the g-forces of slowing down quickly?