lol i have a gokart with that motor. You can find them on ebay, theres usually about 3 a month, but more pop up in the winter. just search "wankel" if you wait untill after winter is over, you can get them for much less money, they demand a premium in the winter since there off of snowmobiles. I'll be hopefully riding mine the next time it's cold out. here are a few vids -

mounted and idling -- YouTube - Sachs Wankel 303cc gokart part 2

after it was rebuilt -- YouTube - REBUILT Sachs 303cc wankel

i could send ya some pictures too if you'd like, from when i rebuilt it. anyway let me know if you need any more info, i've got a lot of specs & rebuild guides that i gathered during the project. also, if you have aim, get ahold of crackheadmel - he is building a gokart with this same motor, but he has the smaller of the twin turbos from a cosmo re motor mounted on it. good luck!