Here is a link to the thread about the stereo I just put in:
http://supraboats.com/bbs/showthread.php?t=3662
If you have any questions, just let me know. I ended up using the the Perko Switch, but I heard great things about both. Depending on what kind of battery you have and how long you are listening to the stereo is going to determine how long it will last. Last weekend my wife had me turn on the boat stereo in the driveway for 3 three hrs while her and her friend were washing cars. We took the boat out later it still started right up. I run everything off of one and if it dies, I will switch to 2 to start and then back to 1 to charge back up. Hope this helps some.
2005 Supra Launch 22 SSV
Semper Fidelis