what system do I have?

[slinxy]

Hi

I just picked up a second audi a3 2.0 tdi and wondering what speaker/audio system I have in the car. I have a center speaker and grill that I think is for a sub but no bose on the grills of the speaker. I'm planning to but in a sony hu, alpine amp and rockford sub in the car and wondering what connector I need to keep the center speaker from working and not lose it.

Thanks