Downsides?
I would think that trying to wash the little monsters without beating up your hands or snagging the washing and drying clothes on them would be a challenge.
Also, not sure what the stall characteristics might be like when you finally do get a stall, especially if you're carving pretty hard at 70 KIAS.
How will you find out aside from flying something with these devices installed and seeing what the stall characteristics are...
Does your stall warning system get modified once the devices are on?
Does your stall warning system currently give you any warning on a high-pitch rate stall at 70 KIAS?