I cut open a few old (discontinued part numbers) filters and made some mounts. Then I used some small speakers from a Phillips home entertainment center channel. They’re rated at 125w. Not sure if that’s rms. Either way, I may run them to a small amp, because they don’t carry as well as the rear speakers. They are loud if you crank them, and they surprisingly have great bass.
This is a picture I couldn’t resist posting. I just think it looks cool.