odd timing, but my boxster has now become my daily driver and I've had this exact same issue for a LONG time on my '00 base TIP. Mine sounds more like it comes from the driver's rear though. Kudos for actually getting a video of this!
Like yours, mine only does it when in motion, and it starts to become audible inside the cabin around 10mph or so. Harder to hear at higher speeds due to engine/road noise, but stop lights/signs are embarrasing!
I have original wheel bearings and just hit 101,000 miles. My first hunch was wheel bearing, but every other vehicle i've had bearing issues with, it's more of a "howl" or a deep, "growly" type sound. This is more of a "rotational squeaky" sound. Brand new tires all the way around on mine, so not a tire issue.
Subscribing!