Can I upgrade my Mac Mini's motherboard and video card?

I just grabbed my Grandpa's old mac mini and I want to use that in lieu of my laptop to play MMOs on or use it as a media hub. I know the video card is attached to the motherboard, and that the hard drive and the ram can be upgraded...but what about the motherboard and video card?|||It's doable but you'd need to buy another mac mini motherboard, with the graphics card attached yet again. Realistically you could use any motherboard but you'd have to hackintosh it then because it wouldnt have apple firmware on the board.