Im not too familiar with installing car audio so this is a noob question. Right now I have the premier deh-980bt. im assuming i needed a wiring harness specific to my car to install the radio. when i buy the f90bt, am i going to have to buy a completely different harness or is the one i have compatible with it? hope that makes sense

No, just cut off the one you got and connect to the new Pioneer one

alright cool. so does this mean the installation is pretty easy. just switch out the new wiring harness, and connect all the other plugs like normal?

And GPS, VSS, and Reverse