Check to ensure all the brake pad clips are in place. I had a similar rattle from the left front end of the my Journey. I did notice that it would not rattle as much when I applied the brakes. Investigating further, I noticed that I was missing one of the brake pad clips. I purchased the brake hardware kit for $5.99 at Autozone which included 8 such clips. I installed a clip at the missing location and issue is now resolved.
Nice added touches! I like the painted grill, gives it a sportier appearance.
One Tip for the future: Consider "blacking out" the rear mufflers hear the exhaust tips. Use a High-Temp Engine black spray paint.