TG16 with CD

I just got a TG-16 with CD unit, a kick boxing game and Keith Courage for about 80 bucks after some trades . I'm a newbie when it comes to the Turbografx, but I want to know what games I can play on it. I've heard things about system cards and the like, but don't know too much about them. I'd like to be able to play Duo games on the system, is that possible?? Any suggestions about the system or games that I should get would be greatly appreciated. Thanks.
There are three major classes of CD System games:

- CD-ROM/CD-ROM2: The "standard" CD system, needs System Card 1/2

- Super CD-ROM2: The "enhanced" CD system, needs Super System Card 3

- Arcade Card CD: Super CD-ROM2 with additional RAM and memory controller, needs an Arcade Card.

System Card 1 was, AFAIK, very short-lived and never released outside Japan. The Arcade Card was also not released outside Japan. Using PC-Engine cards on a TurboGrafx system requires either an adapter or a substantial internal modification. Also AFAIK, each card is backward-compatible with games for earlier cards.

The Arcade Card comes in two versions - Arcade Card Duo is useful only for Duo systems, while Arcade Card Pro is for the standard PC-Engine.
Thanks for the reply. I just found out my system didn't come with a system 2 card
Can I use a System 3 or arcade card to play regular turbo cd games?? Where can I get such cards? I can't find any turbo-grafx versions either on ebay or Thanks.
TurboGrafx versions of the Arcade Card do not exist, as it was only released in Japan. There were plans to release it in the US, but it was canned by NEC/TTI when the TurboGrafx market started dying. The Super System Card / System Card 3 should run (almost? I think there are 1 or 2 incompatible games) all non-Arcade Card games. You might want to check with some of the vendors listed here; expect to pay around $50-80 for a Super System Card. You're a bit less likely to find a normal System Card separately, as it was only sold with the system.