Being in the aftermarket audio field, I would say to please never fall subject to ANY OEM audio upgrade. That goes for the UHFS, Bose, B&O, Burmeister, ect. It is all paper and plastic equipment. And to make it worse, they add tons of speakers because thats what sells the systems. When a potential customer hears that this car has a 20 speaker system and this one has 6.....which one do you think the uneducated customer is going to want? Fact is, they use the cheapest equipment possible (paper and plastic drivers) and EQ the hell out of the OEM source to make it sounds the best possible for what it is made out of. They go to an 8" paper speaker in the front door on the UHFS system because "more bass" means better sound right? I equate great sound with no being able to locate any speakers. That the vocals appear wide and center on the windshield. The the subwoofer sounds like its playing in the dash. Where there is so much separation you can envision how far away the drummer is from the person playing the guitar. That is great sounding audio and it does not matter if you jump into a Ferrari....it is the same crap. A 2017 Lamborghini Superleggera IP570 has the same speaker as a base line Audi A4.
There is a lot that goes into designing a great audio system and with good equipment, less is more. You dont need 20 speakers. You need a good set of front speakers, a good DSP (to fix the OEM signal and make it full again, and to time align your new drivers), some good amplifiers (the sky is the limit....you can add a lot more than you think to the OEM battery) and a decent subwoofer. Don't throw away your money and get the upgraded system from the OEM. If you were to take out the equipment and look and it and hold it next to even a cheap aftermarket speaker, you would feel conned.