Quote Originally Posted by w00tah View Post
There is an easy grommet to use on ATX cars where the clutch pedal would normally go.

Don't use the factory wiring, as stated above. Whatever ground you use, make sure it's sanded to bare metal and secured with a good washer and bolt.
and to add to w00tah's advice; make sure the power wire running to the amp is fused, that way if the amp ever shorts out, it will blow the fuse, rather than making Fire Roasted Aveo.