I'm looking into adding a sub to my system (I have a 2001 King Ranch Supercrew) and I have a friend that told me about making bass blockers for WAY WAY less than you can buy them for. But I need to know the impedence of the stock system on these trucks. I know Ford uses Mach (at least they used to) systems on their higher-end models and unless I remember wrong, they're made by Infinity (I think) so I imagine it's different than stock. Anyway, I need to know the impedence on the system so I can get these things put together.

Thanks

Clint