It's got a gauge mileage (starts at zero), as well as a programmable odometer.
Also, it'll work Aracer and the 5-speed. There's a learning mode to figure out the gear you're in, as well as a speedo calibration function for whatever tire diameter/gear ratio you choose.
The main reason I bought it was to consolidate all the add-ons into one. It's got what the stock cluster has, plus three color options, gear indicator, speed calibrator, max values (temp, speed) and EOT readout.