I wouldn't even take the time to take it to a dealer......as F.G. says "Crap is as crap does".
Curious, replaced the main Bose amplifier or just the antenna amplifier? Regardless - Of course a new amplifier didn't fix the problem - a new antenna amplifier won't either - these new gen radio/Nav heads even with the $1000 Bose system and amplifier option have crapo front ends (worse than my gen1) that require a strong signal to work properly. They even contain an antenna amplifier to boost the signal which I figure amplifies more noise than signal. I'm in the same boat living in a mountainous fringe area. A far cry from GM's predecessor radio/Nav head in my '16 Silverado whose $500 Bose system has a really strong front end - even has the HD radio feature - can almost pull in signals from Mars. Plus it can play mp4 videos via USB on the front Nav screen when parked whereas the '18 plays dumb and cannot find the same files.
Could also be an effort to save bucks on a cheaper radio or maybe to pump up sales of the XM service. Use locals stations for news only, otherwise load your albums on a chip and forget the radio.
Current Chevys -'19 Silverado RST;'18 Malibu LT Redline;'18 Traverse Premier Redline<br /><br />Previous Chevys:16 Silverado LT;16 Malibu LT2;'17 Impala;'16 MalibuLT;'15 Camaro LS;'15 Traverse; '13,'12 and '07 Avalanche LTs; '11 Tahoe LT; '13 &'11 Malibu LTs; '08 Trailblazer;'06 Colorado WT..... Chrysler era.....'80 Citation;'75 Impala;'72 Chevelle;'69 Camaro R/T;'65 Impala SS;'62 Nova