I am deciding whether to order a ZR with or with out nav. If I order it with NAV, I want to add the AVX-2494 instead of the AVN-2454.

Since the AVX does not have RCA out puts, will the sound basically sound the same if I add an amp to the unit or will a headunit sound better with rca pre-outs than one with out them?

Just curious, all of headunits that I have hadd in my cars had pre-outs with amps connected.