Ray,
I also have the Marantz. My understanding is that the Marantz will only accept a signal via the VGA input at its native resolution - 800 by 600. I have used a HTPC with this projector and what a difference! The Elite should pretty much do the same thing.
Bypassing the internal processing of most projectors is simply the thing to do.
Alan was kind enough to help me with my initial setup (HTPC and Marantz). Go to page 15 of your manual and read it carefully and make the appropiate adjustments. You will lose all settings from the projecor except contrast. You don't even retain "brightness"! If the Elite has colour, tint etc. then you will need these, if not, then hopefully your DVD player has them.
I have baffled the light from the front fan vent and masked my screen. I use the da-lite Hipower screen with it and when set up properly this projector is really good!
The Marantz has something called the "white enhancer" - I wonder if this is similar to the "white segment" on the LT150? I don't think so since having it on or off doesn't make as dramatic a difference as having the "white segment" on or off with the LT150.
Cheers,
Grant