Has anyone done an amplifier install in a third gen (2002-2006) Nissan Altima?...I can't seem to find a good existing rubber grommet to use, am I stuck with drilling a hole in the firewall?

Thanks in advance,
Andy.

Buy a grommet, costs $1. Works wonders. I have not tried anything like that in an Altima, to answer your question.

On the passenger side firewall there is a grommet.