I just wanted a window side panel period for my F51, because when I got it I didn't think I would want it and rethought my position later only to find out they're only sold in Australia. Fast forward to yesterday and I see that there's a tempered glass side panel now listed, however out of stock...
https://ttstoreusa.com/product/core-v51-tempered-glass-upgrade-kit/
http://ttpremium.com/product/core-v51-tempered-glass-upgrade-kit/
While I've greatly enjoyed the case the struggle on something so simple is really putting a damper on wanting to recommend tt or buy another down the road.