i just ran 4ga through the passenger side gromet today. it was hell of hard to get the fat wire through the rubber. especially when its behind the engine. and i barely had enough wire to go all the way to the trunk. but it worked. id reccomend the driver side. wish i would have known about it before today.

off topic: i gotta question for some of the more experienced audio guys.
Iv got a 1000w (peak) amp, and 2 12's. Is 4ga big enough? the package says 1800w but i hear all the stories about people with 1000w amps running 0ga. does it really make that much of a difference?

 

4ga will suffice but you are pushing it to the barrier. Personally I would go with at least 2ga. If you plan on putting another amp in for the rest of your speaker in the future than I'd diffenately go 2ga and t5o be sure I'd just move on up to 1/0. Big amps yearn for power and with you having two 12's running off it your system is gonna want that power. It may struggle at times to get what it needs through 4ga.