2002 Altima Firewall?

I am installing subs in my 02 Altima. I have put subs in numerous cars, yet I cant find any openings. Anyone installed subs in an 02 Altima? One guy told me to go through the wheel well into the fender into the car, one said to run it under the body of the car and drill through the trunk which sounds 100% retarded, and others said to just drill through the firewall. Its an automatic so i was going to drill where the clutch petal would belong but before i do any other ideas? All my cars Ive owned i been lucky to have a rubber boot that you can pull out to have a pre-drilled hole into my car. If you going to say drill through the fire wall any specific drill bits? Or just standard metal drill bit will do.