i've got a 2001 A6 2.7t and i was wanted to add a little bass to the factory system but not anything crazy.i was considering a bass tube or something similar. also i wanted to put an indash nav system. any suggestions???

 

Well i will have a DIY soon for a fiberglass sub enclosure for a 10" sub to fit in the tool/cd changer compartment. (i've been a bit busy lately)

The navi i dont have a suggestion for though.