stereo troubles

[BMW X5]

ok guys i'm hoping someone here can lead me in the right direction this might be long so thanks for your patience.

this refers to MY '02 4.4 with DSP and NAV system.

when i picked it up about 4months ago a few of the speakers were not working properly and the sound kept on cutting in and out gave a feeling of a deaf sound almost it didnt feel full . so i took it to the $tealer they looked at it changed out speakers which were blown from a few days prior when they began crackling. picked the car up speakers seemed to work yet the cutting in and out still persisted . took it back to the shop had them look at it this time they swapped out the radio unit since they found a tsb which stated that if radio cuts in and out change the unit. so got the car and again for few days it worked fine at this point im confused . later on i found a leak in the trunk which coincided with my speakers crackling again. so took it back to the shop they took care of the leak and changed the amp which they claim and at this point i figured was the only thing left to swap out but due to the water it was actually damaged so new amp. still now i have no leak new amp new radio supposedly new speakers and the stereo still cuts in and out its more noticeable with the DSP on so im thinking maybe its DSP? is there anyone here who has any idea because i have no clue and at this point im um a bit to say the least