Yeah you need a DX or a Flatmii or another 4th generation chip to use it. Since the Zero and all other 3rd (and 2nd and 1st) generation chips rely on you having a controller chip you're stuck using one of those. The GC2-D3 version doesn't have a controller chip; they integrated all the controller chip's features into another chip on the board, I imagine to combat piracy because this is how all the modchips had been working. Lucky for us modchip makers were one step ahead of Nintendo

so at least you have the option of getting a DX or another 4th gen chip. From what I hear the DX is a pretty cool guy, the only thing it doesn't support is running the drive at 3x and I think it might not include the gamecube audio fix.
[Only Registered Users Can See Links. Click Here To Register] that outlines its features. I'm pretty sure none of the other chips out there have anything this doesn't have, except Flatmii which has some sort of complicated method of streaming game images from your computer.