Yes it is possible to do so. In fact, I have a '17 QX30 Premium with the Tech Pkg, and even though it came with the Bose speakers all around and a factory Bose Sub+Amp from I added a small 8" Phoenix Gold Subwoofer and amplifier. And, "Oh boy" does it sound amazing! I wasn't going for anything which would ultimately make my rear wipers rattle, but wanted to feel the bass when listening to music. The acoustics of the QX30 are excellent for smaller subwoofer enclosures. Trust me, you'll be blown away!
Now I´m realizing that you have Bose Sound system (I have ordinary sound system), so probably you have only amplified your new sub Signal. I tried to amplify the complete signal to the speakers (all of them)... this could be the keyHi philloliveira, haven´t you had problems with the active noise cancellation system of our car and the amplifier?
How do you do it?
I Installed an amplifier, and at first (with the car in the mechanich´s garage) it was great... but when I started to drive, It produced an extra loud noise coming form the speakers that was directly related with the engine RPM.
We did´nt found the way to avoid it, so We finally had to uninstall the amplifier