Where to find a 4Mb expansion for a Saturn?

Can anyone tell me where I can get a 4Mb Ram expansion cart. for my Saturn? The one that lets you play X-men Vs. Street Fighter? The officail Sega one would be the best but I'm desperate so I'm not too fussed. Thanks a lot.

(Edited by Funkstar De Luxe at 3:05 pm on Jan. 16, 2002)
My friend did mine and it works fine. He did US/JAP switch...althoguh I think we should've done a three region one but i can always region switch games with software....i doubt i'm going to buy an PAL games anytime soon.

I think the total cost to do a switch for me was about 5-6 US dollars.

the us/jap switch is rather easy compared to the 50/60 switch, but if you have a US console, you really dont need the 50/60 switch, as most games that came out in europe came out in america or japan as well