Found this link in another forum
Folks, I found this link in another forum with really good instructions and photos. Thought I would pass it along.
Installed new front speakers - Page 9 - The Mustang Source - Ford Mustang Forums
2012 California Special Convertible / Ebony Black / 5.0 liter / MT-82 / GT500 Axle Backs with resonator delete / Steeda Tri-Ax shifter & base bushing / Airaid CAI / BMR LCAs / BMR Relocation Brackets / BMR Adjustable UCA & Bracket / BMR Adjustable Panhard Bar / Steeda Sport Springs / GT500 Strut Mounts / Koni STR.Ts / Shaker 500 with Infinity 6832CFs / Redline hood strut / Redline leather shifter & E-brake boots