How to Install GROM Bluetooth with Stock Head Unit with Nav BMW E46 M3

Went back and forth deciding if I should spend $500+ on a new head unit just for Bluetooth and tear up my interior to run the long cable from the back to the front. Found Grom to be the best solution for my needs. Also added the Rennline Phone Holder. Here&link to items below Grom Bluetooth Adapter Pry Tool Rennline Phone Mount