Reubent this gentleman has everything he needs already.
OP all you need to do is to take the front left and right line level outputs from your Marantz into an analog input of the new integrated amplifier.
You can use one with or without a home theater bypass function.
If the amp has a home theater bybass all you have to do is to select that input on the new integrated amp and then play your theater the same way that you do now.
If the amp does not then all you have to do Is to find the volume that gives you equal levels when doing your calibration. You can contact us if you have any questions on how to do this.
A warmer more full bodied sounding integrated will really make those Triangles sing.
Another way is to run an optical output from the TV to an integrated with a built in dac and in that way the audio for home theater will also be on the system, then the TV must be set to output PCM.
Dave and Troy
Audio Doctor NJ