....so....much...ignorance.
Seriously, not to be mean people, but don't offer advice on compatibility unless you know what you're talking about. That's just plain mean and misleading.
The Mega CD/Sega CD all have region lockouts through the internal EPROM which is encoded for the region. You can do mods to remove the EPROM and replace with a multi-bios but I hear this is quite a pain and certainly not as easy as switching with MVS PCBs. There's also the problem of identifying the EPROM which there is no known documetation for I believe (with the Laseractive and CDX and some others as far as I know). Fortunately there is a solution:
Google "Conv SegaCD" and "SegaCD Conv" These are two great programs that will convert 90%+of all Sega CD ISOs to the region you want for play on the Laseractive/Sega CD/Mega CD
Also, the Sega pack will fit oversized carts but you must mod the system internally to play later Mega Drive games with lockout capability (there are lists online for which carts have lockout). The mod is possible though and instructions can be found on
www.gamesx.com
-Segasonicfan