I was hoping someone that has gone through this situation or some senior members could help me out with this one.

I am thinking about buying a used 2004 Acura TL but I can't decide whether I should get a Navi or Non-Navi model. Eventually I want to replace all four speakers, install Jl Audio W6, add the appropriate amps, but more importantly install an Alpine W505 double DIN deck.

And thats where the problem lies.

If i go with the non navi model....I can probably just replace the stock double din deck and use the W505 as it was meant to be used. This way i save some money on the car and I dont risk losing any of the existing navigation features/voice command features. However, if you know what the climate/music dispaly looks like on the non navi model you'll which that video could be watched instead of the climate control/music details.

Alternatively, If I go with the Navigation model...The climate control/music readout are in a much better spot along the top of the heater vents instead of just the clock that is there on the non navi model. For this choice i would still replace the stock deck with the Alpine W505. However this also raises a couple concerns:
Am I going to lost any voice control or volume control on the steering whel by doing this?
Is this going to be possible? Given the situation....

Any thoughts on this issue would be appreciated.

Thanks in advance!!