Does anyone know on a 2015 M235i if you can add or replace a factory amplifier with an after market one. And if so do you need to use something like the "Aftershock, Front Row, Etc, to allow you to connect the new amps with RCA's. Also any advice on a better speaker choice than the, already upgraded, H&K speakers would be much appreciated. I got the new car blues, fortunately all of the engine mods are a cakewalk but this stereo stuff is over-complicated as usual!
Thanks,
David