Stonecld33

Can someone give some insight or maybe an idea on what to do. Here is the situation. I have a 2005 f-150 lariat screw and I want to install a aftermarket kenwood head unit. Every radio harness adapter that allows you to be able to install an aftermarket head unit without cutting the stock plug off but the ones I see for sale always says in the description it will not work for trucks with the r.a.p system( where the radio stays on after you take the key out and shuts off when you open the door).so I basically need to know is there a radio harness adapter made just for that system to hookup an aftermarket radio or do I just have to cut the plug off from the harness and hard wire the head unit, but I would like to keep that option of the radio staying on after the key is removed and if I don't keep it will it mess anything up. I have a non-amplified system with 4 speakers. Here is some of my confusion. The stock head unit that came with the truck has 24 tabs on it for the plug coming in from the truck harness. The plug on that harness has 17 wires. Any help would be greatly appreciated.I really new to this forum and hope this doesn't sound like a dumb question.lol

Thanks again,
Mark