Maxima Forums - 5.5 Gen Maxima Bose System Clarity ?

Whats going on all, so I am not here to ask a noob question about not having sound or my radio having bad reception lets get that out of the way.
Ive had 3 maximas thus far (97,99 and now 2003) and all have had bose for better or worse BUT this 2003 i now have (titanium edition) i equipped THE SAME head unit i have had in each one of the mentioned maxima's (Pioneer AVH-3300BT) every time buying a new Harness for the car for whatever its worth (7551 i believe its called it has the RCA and all that jazz it works)
My Issue is now after i install the radio and get everything squared away so i can continue to use the bose speaker system and sub this 03' came with THAT SOUNDED MINTTTTT with the stock head unit ... it now well ... leaves alot to want. I cant really turn it up high as i want because its very lack luster and it distorts even when i have the audio setting on "vocal" to reduce the bass. I have Re-Grounded the headunit as well as that brown/white wire so the trip button works on my steering wheel and fashioned a new ring terminal ground just encase so it makes the best connection.
Like i said before ive used this head unit for years now with my other maximas and its been phenomenal ! before i rip out what i thought was a excellent bose system to replace it with new speakers is there anything i should investigate? Some other Culprit to the distortion and poor sound quality? i used the RCA outputs on the back as i read on the forum is used so the interference doesnt happen wiht the head unit and the bose system trying to power the signal. let me mention that songs WITHOUT heavy bass still scream but as soon as any bass is introduced into the song it becomes very distorted and gross even with the gains down on base. I do have the other style wiring harness (i believe 7550) that is for standard maximas without bose that i ordered encase i wanted to swap the speakers out id need it instead of running components.

any help or suggestions would be great ! I appreciate it and currently having so much enjoyment getting back on the forum/messing with my new (to me) Maxima !

side note i am open to replacing the speakers but since i got the car off a older gentlemen (1 owner) with 88k miles on it I kinda was thinking the speakers would hardly be broken in since he listened to talk radio all the time judging by his presets on the factory head unit.