Nathan- Yes it dose state on the site that you could use your existing egt probe and greddys are acceptable, If u have not read it yet

Scharok- All egt probes should be installed on the exhaust manifold. I do not recommend you install it on the downpipe. The wide band is a separate unit and you don't need too splice any wires. The wide band will simply be installed in the downpipe with a $7 bung as i had already mentioned. You will have too tap wires into the ecu for a rpm,throttle,power source (if desired) and for our convenience they have colored the wires too match the SAFC wires.