firewall hole ?

[bcbrassard]

Bad no, but not needed IMO. Frame/Body grounds will will work just as well.

[Pioneerchuck]

If your car is rust free then a strut mount ground will work but if you even have the slightest sign of rust or corrosion then do a dedicated run. And on your car there should be enough open room on the bottom left side of the firewall (by the E brake) where you can drill a hole.