yes.
the mic will clip.
if you see a red light come on (and stay on) on the control unit, you're fucked.

just run the pad, and you'll be golden. the mic is *very* sensitive, and it will clip w/o the pad engaged.
get a pair of C batteries for it, phantom power it from the box (dont ask me why, i just like it that way).
dont pad the deck.
the signal will be a HOT mic signal, or a WEAK line level. its sort of a matter of which one you want to deal with. cranking open the attenuation w/the line level (what i'd do), or using a lot (likely) on the mic input.
I'd go line in, run the Marantz around 8. the pad shouldn't be needed there.