Re: 8400bh vs 8053 eclipse.
I believe you have to use it with the "Eclipse Commander"....that's if my memory serves me right. That is a very nice SQ geared HU. I think it also has an auxillary input.
It depends on what you really want out of your system, and which head unit will help you get there. Take a close look at this, then weigh the pros and cons of both HU's.
2010 Nissan Maxima SV Premium with OEM DVD/Navigation HU
HERTZ: Mille ML 280
Audison: Voce AV 6.5
Boston Acoustics: GT-2125, GT-2200, G510RS