Hey guys just picked up an Used edge juice w/attitude cs2 for a good deal. So I already have egt, trans and fuel pressure gauges on my pillar mount. So basically When I go to install the edge  I’m wondering do I have to install all of the sensors that come with the edge or am I able to splice the sensor wires on the edge harness into the appropriate wires for the gauges I already have? 

I'm not sure that's a good idea, I think some gauges are calibrated to work with specific sensors.  I am in the same boat you are, had the gauges and then got the juice box.  I just run both EGT's and both fuel PSI just in different locations.  I haven't installed the other fluid temp sensor yet, had a bad incident last time I tried and am a bit apprehensive now.