No you dont, 2008+ cars are OBD II CAN enabled only, i did just do an ecu mod that allows CAN obd2+ for 2007 cars for the DASH2+CAN+DL1. you want the CAN ECU interface if you're going to try to attempt reading the basic info, speed, rpm, coolant temp, fuel level.
however i've gotta say, i spent 4 long days trying to get the damn thing to work properly, i did originally do a decode for the stock CAN message, and I could never get the RPM right, it'd display ok one place, then not another, and there aren't many parameters, i wanted to keep the old CAN protocol because i thought the owner wanted keep the original cluster, once i found he was ok ditching it, i spent a few long hours redoing the ecu at the track for the CAN OBD2, i got it all working again in the snoop side, then we got the ECU programmed up but on track the DASH2 just kept loosing the information, it may be the dash2 itself was faulty, but it drove me consistently nuts.
I couldn't figure out a way to get it push fuel level over the obdii can though.