alright i got a new head unit for the cruiser it's a pioneer deh-p3600. I got the regular wiring harness that comes with the unit and the celica harness that you can get from crutchfield. I'm hoping to install it myself with the help of my brother who is very good with car stereo stuff. So how hard is it to install a head unit in these beasts and is there anything i'll need to do or look out for?