I had several rattles after installing my delete pipes during the 200 mile relearn period.

I just kept a few wrenches and sockets handy when I'd pull into my driveway.

1) the tailpipe section had shifted and was hitting the heat shield for the spare.

2) the c clamps required one section to be tightened. (Allowed tailpipe section to twist a bit hitting heat shield again)

3) both hangar clamps needed snugged up.

Went in that order, each presented after about 50 miles or so and came after one another (or I didn't notice it until fixing the first)