Stock sub and Pioneer AVIC-F700BT

[YukonJacks]

Nothings simple, while installing a Pioneer AVIC-F700BT in my "00" SLT Yukon, I was getting ready to solder the wire harness when I read in the Pioneer install book depending on the subs watts depends on how to wire up the rear speakers to the sub. The manual asks if it is 70w. Does anyone know or do I have to play disassemble the interior

Any help will be greatly appreciated