stock radio help

I have a 98 deville d'elegance. I am leaving the stock radio in and adding an amplifier and subwoofer in the trunk. It is NOT the Bose system. I don't want to disturb the original wiring from the stock radio since I've heard and read about possible electrical problems occuring when you do that. I have the amp, subwoofer, line output converter (LOC) and all neccesary wiring and I have pretty much run all the wiring (power, ground) back to the trunk. I will be connecting the LOC to the rear speaker wiring from inside the trunk and then connecting the LOC to the amp with an RCA patch cord between the LOC and amp and then connect the sub to the amp. My question is: "Where is the best place to connect the remote turn on lead wire?" There is a fuse panel in the trunk and there are the plug-in connectors behind the stock radio. Which would be best and if behind the stock radio is better, which wire do I connect it to, or if the fuse panel is better, which fuse do I use??? ? sorry for all the extra stuff, I just want to do it right. Thanks!!!:confused::smokin: