stereo replacement

Hello to the members of the forum. I am the proud new owner of my first Acura...a 2006 TL with Nav. I've owned a Honda 1980 Accord in the past...well, several decades ago and recently decided to "try" an Acura. Recently found a 2006 TL for sale from a non-Acura dealership that was a one-owner...

I have a 2001 TL and want to replace the head unit. Just bought a kenwood mp345u and want to get it installed. i've been told I need to replace all my bose speakers (4x 6.5 speakers, sub) and bypass the amp or the system won't work. very discouraged, not a lot of money, please help. much...