I just realized the 40 watt thing i have is a "stereo booster" thats why it uses direct line in. And the sub i just got is the Aura Force 10 ...specs:


Proly not the highest quality, but it was free so what can i say...lol

Honestly the Force 10 is a really nice product. Although the Optima is crap. To do this right you should invest in a decent amplifier. also you will need to get a Line Level Converter. What this does is take the signal coming off of your radio (meant for your speakers) and turns it into something the amp can use. This comes with tradeoffs though. Not to scare ya but it will increase the wiring, the complexity, and you'll need room for the amp, and sub. It'* funny, ever since I heard good sound I've haven't minded to make room in my trunk.