New Sub, Proper setup help
 

Basically I have an Alpine Vpower mono 400w @2ohm amp. Ive been running it @ 2ohms on a JBL 12" 300rms. I keep breaking a wire because of its cheap design, and because of the bass vibrations, its very hard to fix properly so I sold it to my friend. Today I just bought an Alpine Type R 12" 500rms.

My setup now is that Alpine Vpower amp and I believe 4 gauge wiring for power and grounds. With my JBL I got light dimming at higher volumes. Any suggestions to aid it.

I have a volks golf 1998. I believe its a 70amp alternator. Ill doubt check. Could be 90 also....

Now im just wondering, when the alpine gets here. Are there box specifications that I need to prevent damage.... etc. I have a fairly small low profile box that might not even fit the 7.7 inch long Type R. Im new to the car audio scene. I know electricity, because im taking an auto mechanics course. If i left any info out please let me know.

Thanks
Kyle