I've been reading up on the sound system for MS. Here is what I know: UHFS shares the same front and rear speakers as the Base System. The front and rear speakers are the same. More power is been distributed to drive the front speakers. This is apparent because the front has bigger better sound than the rear. I have the standard base sound system on my MS. I know SC won't add UHFS afterwards. I am looking at the LH part 1 to replace all 4 speakers. My question though is, even if I were to replace all 4 speakers with the LH, would the rear still be somewhat muted due to how Tesla has configured the overall sound system?