I ran 4 gauge a while back and I just used the factory holes in the firewall. Then ran it under the plastic lining of the door(quite simple), which takes you to the trunk. How you get around your back seat once your there is easy. Hardest part by far was the firewall. Hope this helps

2k silver svt #1721
1. custom stereo
2. KKM induction kit
3. eibach springs
4. sho shop y
5. custom catback
6. A6 2-way side markers (clear)
7. Pro-M 75mm
8. Illuminated moonroof switch
9. removed door ding guards
10. more to come..
"Ignorance breeds stupidity.."