14 channels seems excessive even for a luxury vehicle. Maybe it has 14 speakers. 2 per door (mid+tweeter), 4 on the dash or rear pillars, maybe a mix of 2 tweeters on the dash and 2 on the rear pillars. Usually mids and tweeters share a channel so that would be 6 full range channels. 1 center dash and 1 sub. 8 channels sounds more like it. Can you verify where each speaker is located?
There are 8 channel amps that can power every speaker in there. The thing is that replacing the amp does not guarantee the popping/static will disappear, the radio may be the issue. Testing may be frustrating if you are not used to dabbling in car audio.