I use the Mychron3 Basic 2T. It get 2 Temp. ,Laptime and RPM.
http://www.me-mo-tec.de/html/index2.htm (German side)
http://www.aimsports.com/karting/index.html
U can use EGT,CHT, Oil, and H2O Sensor. The MyChron 4 is the newes and i think the older Basic3 will gets cheaper.