im on my way of making my own. i say if you know how to crimp big wires, do it yourself. the "kits" charges a load of money.

4 guage wire cost $.99 per feet. you wont need more than 10 feet. crimps cost $.50 per. and if you dont have a good crimper, $20 can get you an impact crimper for working wth the 4 guage. then put in some time to sand the paint off the chassis...:dunno:

im planning on using 4 guage wires from these points:

-valve cover to chassis
-negative battery terminal to chassis
-positive lead on alternator to battery (as well as keeping the stock lead)

robert made a good write up in the car audio section.