Where can i wire a ground to? I should be able to attach a ground to anywhere on the frame or subframe right? or do i have to wire a ground to the battery?

What are you grounding? Technically yes, you can ground to anywhere on the frame, but the quality of the connection desired is what will determine if you want to ground there or run a cable to the battery.

I thoughtaluminum doesn't make a good ground, does it?

Find out where you battery is grounded to. If it is big enough you may be able to attach there.