I found a 1 inch hole in the firewall...it wasn't a hassle for me! But I know it would be easier to just hook them to the stock wires. The only hassle I had was mounting them.
Hey, you mind sharing a pic or description as to where the hole is??
The hole is on the driver side of the engine bay behind the strut tower. To get the hole exposed though you have to do it from the inside of the car. Take the black cover off that'* under the steering wheel (the cover that'* over the fuses and wires and stuff) I think you have to pull back the carpeting just a bit. You will see a black cable on the left running into the car from the engine bay.
TIP: From inside the engine bay it'* easier to see that cable running into the car (behind the strut tower)
From inside the car once you find that cable there is a rubber seal that you twist off and pull back. Once you do that the hole is exposed and it'* very easy to run the wires through.
I don't have a pic so I wanted to describe it the best I could. Basically, find that cable running into the firewall from inside the engine bay. Then from inside the car find that same cable and where it meets the firewall pull the seal off.
I'll see if I can get a pic soon, but try to find it first and let me know if you know what I'm talking about