Wire route for aftermarket amp in '95

[The Jester]

Hi there everyone.

I own a 95 mustang that I am planning on adding an aftermarket Amp and sub box to in the near future.

Ive purchased all of my wire, fuse holders ect and am just about ready to tear some interior panels out and run my high current + lead for the amp but have a couple quick questions i hope somone can answer for me.

1) Is there a lug in the power distribution panel under the hood capable of providing enough current to reliably power my amp?, I will probley tap directly off the battery otherwise, Any Ideas?.

2) Is there already a hole in my firewall for me to pass the wire through or am i goig to have to drill one?.. Im fairly paranoid about punching holes in my firewall so i would perfer to use an existing hole is possable. The wire i have purchased is 4 guage inteded for car audio applications

3) is there anything I need to take into consideration as far as routing the wire along the length of the car.. I was planning to use the wire channel in the door jamb.

Best reagrds and thanks in advance for your advice
Corey