Dang, wish I knew about the antenna when I installed mine, twice, LOL, I use the evil cartman method on the 11 V6, but just tapped into the right rear speaker for the sub input on the 12 GT
The 12" MTX with Kenwood Amp, bridged to 150 watts RMS is plenty for me, and that setup is almost 18 years old and still works great, had it in many cars.
2012 GT Premuim A/T Sterling Gray, Loaded, Tinted, Steeda 93 Tune, JLT Oil catch can, 12" MTX Sub, CHE LCA's, GT500's, Boss/CS Lower Fascia W/foglights.
2011 V6 M/T traded for 2012 GT
2007 GT M/T traded for CRV