Wire gauge size VS Amp wattage

[grayguy]

I am totally a newb in the car stereo department, and am going to be putting a sub in my wifes WRX. I am wondering if i am running a 250w amp, how big of wire should I run to the rear of the car to the amp? Here is the sub I have:

http://www.crutchfield.com/p_107DXI108/Polk-Audio-DXi-108.html

and here is the amp I'm using:

http://www.crutchfield.com/S-PhEPSkpS8Yx/p_130GMX372/Pioneer-GM-X372.html

According to bestbuy these should work well together, but what gauge wire should I run, is 4ga sufficient?

[decke48]

8 gauge will do for under 450 watts, you can run 4 gauge to the back for future uses. but will be overkill

[Wiscon_Mark]

agreed, 8 gauge will be fine. But if you ever plan on running bigger go 6 or 4 gauge and only do it once.

Make sure you clean the threads and use a nice, new bolt for whatever your grounding point is!

[grayguy]

I'm gonna just do a 4ga ground wire and 4ga power wire. Thanks guys!

[unsullied_spy]

I'm gonna just do a 4ga ground wire and 4ga power wire. Thanks guys!
Not at all a bad idea. If you upgrade in the future it is so much nicer to not have to run that wire again! You won't hurt a thing by going too big.