I am shopping for a new stereo and on Crutchfield when I put in my truck and look at needed wiring, it indicates I need this "iDatalink Maestro ADS-MRR Interface Module" (https://www.crutchfield.com/p_794ADSMRR/iDatalink-Maestro-ADS-MRR-Interface-Module.html) to retain steering wheel audio controls and the existing amp. Is this really necessary? The thing costs $130. Seems really expensive and that's not including the needed wiring for it which is another $40. Is it possible to just retain steering wheel controls and not the factory amp? The thing seems like it sucks anyway.