Is it absolutely necessary to upgrade the headunit? I have a pair of BA's in the rear, and plan on upgrading the components to BA's as well. I would like to power these with an amp (or amps) and also might possibly put in a basslink. What do you guys recommend?

 

I assume you have a BOSE HU? In my opinion, the HU is the weakest link in the BOSE system. Upgrade and you'll probably notice the difference. Absolutely necessary? No..

 

I ditto that.

I noticed a difference when I got an eclipse hu after going through 5 bose hu. The bass was more crisp and the sound quality was better, more clear.

When I changed my speakers...now that's a different story lol.