AGP graphics card's are backwards compatible, I doubt that AGP 4X 2.0 is required it is probably just supported. If you can tell us specifically which GeForce 2 you want to get and what motherboard you are using we can give you a more exact answer.
Also, DO NOT upgrade your motherboard just to get AGP 4X. That would be a complete waste, matter of fact AGP texturing is a waste. If you don't understand why and need a full explanation let me know.