$100 is a **** good price. I had one and it was quite loud before it blew. I sold it for $30 shipped blown, so $100 picked up is a great price. And quad coil isn't a pain - you have more wiring options that way.
Whats the MSRP? isn't it like $600? For a $100 you could resell it and make a few bucks, then put that money towards some better products... just my 2 cents