Save yourself the money and go to your local car audio place and get some connectors with some 8 awg wire and do it yourself. Or go to eBay and get a Buddy Club Condenser for about $135 shipped. I love mine.
i have one of the ebay ground kits (it's just a generic ground kit) i haven't installed. I just got it to try and match the BCC's 3 wires' colors and to ground other parts. When I got it, it looked like something I could've bought from a flea market- and quite heavy too.
the biggest concern you'll have is matching the lengths of wire to whatever you want to ground; just 'cause the auction says its for a car doesn't mean anything in my book. That's half the reason most people cut their own. That being said I bought one for my previous car but never got around to installing it. I plan on putting it on once the whether is nicer. I haven't even checked cable lenghts. I also got a voltage stabilizer with the auctions. Its definitely not as fancy as these BCCs, but I imagine its just a basic voltage regulating circuit to prevent spikes and probably has some capacitive/rectifier properties to help with drops. Atleast it doesn't have any LEDs. I've actually had it on my old car for about 4 months and no gain or harm, but its not the best electrical system either.
long story short if you don't feel like making your own then $40 for some precut wires, a battery post and hopefully a voltage stabilizer isn't the worst use of money. Especially if you go ahead and ground the TB, alternator, fuel rail, block and headlights.
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