conton

Where is teh best place to run wires for an amp? Is there a good hole in the firewall already? Will I need to drill?

hiredgoon

depends what year your car is, but generally there is a hole in the firewall under the glovebox, that the main wires run through to the battery. This is covered by a rubber gasket in the engine bay. Probably the easiest to do, all you need is an x-acto knife, screwdriver and some zip ties.

conton

3rd Gen

Shawn

There is also a hole on the drivers side above the clutch pedal. If you look up in there you'll see it with a carpet flap covering it. This is the hole my shop used to get through the firewall when they installed the starter/security. You could run the power wire from your battery through here and down the left side of the car. Then run the RCA's and other wires down the right side.
If you lay down by the pedals with a flash light I guarantee you'll see the opening

mazdaspeedwest

make sure to run your power wires down one side of the car and the signal (RCAs) down the other side to maximize your chances for a low to no noise soundfloor. fuse the power wire no more than 18" from the battery. protect the power wire if it passes over or through any sharp edges.

MP3-Owner

All good info...You can see my wire in these photos Here (Look under New cone filter)
BTW...I ran my 4gauge power wire through the hole on the drivers side that Shawn was talking about.