Maybe I'm getting old, but I found the Toyota nav to be more than sufficient. I probably would have upgraded to aftermarket, however I found the non lagging steering wheel audio controls a plus. I further enjoy using the voice activated button for nav and BT, along with the answer/disconnect BT buttons on the steering wheel. It;s just too well integrated to give up, which is why I went for stock nav. Plus the JBL amp/speakers aren't bad, (except for the sub).
Naw I doubt your Getting old don't say that i'm a Tundra owner too (31 now) . I think feature for feature Value for Value Oem really is very low on budget features and content vs features your gaining on a Z1,zZ,Z3. Sure Factory look's great on paper but can it mulitasking on playing a movie to a rear monitor and do Navigation at the same time (hdd is better vs dvd rom ). I'm personally Feed up with Toyota Navigation used on the Avalon it was a joke not having Non touch screen and the lock's out were truely a joke in this class. Far as features on the steering wheel I have all that too and it can be retained on a Pac steering wheel controls so No your not loosing that on the aftermarket side. JbL speakers are "OK" but then again it's factory and doesn't really provide a system to start with.Im not really a JBl fan either way I review sound Toyota need's to offer a better selection.
Erik