In order to get the Killler Instinct 1 and 2 MAME ROMS to run, you have to download the kinst 1 and 2 HDD images, the hdcomp.exe from the DOS version from MAME 32 v.63b, and the kinst HDD image convertor, which converts the kinst 1 and 2 HDD images to kinst.chd. Don't ask where to get these files. Put the kinst.chd into the kinst rom folder and expect to get some shitty speeds even on the top of the line CPUs. I have a HP Pavilion P4 1.4Ghz CPU, Geforce 4 Ti 4600, 1GB of PC 800 RDRAM, and a 7200RPM 60GB maxtor HDD w/ Windows XP, and Killer Instinct 1 and 2 runs like shit on my computer. You would need to at least have a 5Ghz CPU to run that game at 100%, so I hope your joking if you ask if Killer Instinct 1 and 2 will be able to be played on XBOX MAME at 733Mhz/64MB of RAM. Like Bolch said, your best bet is to hope that the new n64 emulator in development works and supports KI Gold.