Hi guys....i have a stock 04 and just noticed on the inside of my rear left rim i am missing those little siver squares that are on the other rims......what exactly are they and is it nesseceary to replace them?? thanks

 

They are wheel weights to balance the rim. Rims are not uniform and don't always need to be balanced in the exact same way. Then there are the wheel weights that are put on by the tire balancing shop. These compensate for irregularities in the tire.

 

You can "throw" weights off a rim as well. I wouldn't worry unless you're getting a vibration. If you do think a wheel is out of balance, a simple balancing at a tire shop will do the trick.

 

yeah if you're car doesn't "vibrate" at any particular speed, don't worry about it.