160w audio system is all they specify from honda on the non-si trim. They do not note the RMS of the radio unit itself, but it's made by clarion. You may be able to get somewhere by contacting them.
typically most stock head units run class AB/class D amps run on the 12DC output (and usually don't have any voltage boosters)
This translates to roughly 18W RMS - which is well within what most aftermarket speakers take, if that's what you're worried about