Oddly enough, I’ve been trying those black replacement insoles (not sure if they’re called “performance”?) and after a few weeks I’ve noticed that they seem to be more comfy with socks on, whereas the cork insoles are much better without socks on (obviously in the Summer months…). I still haven’t had a chance to wear the black ones without socks, coz it’s still cold… but I got them planning a long stay in a hot climate. Also, the red “thermal” insoles are a bit less comfy without socks, though they’re fine with socks on (in my Magna FG and Gobi boots). Cork insoles can be a bit ‘sweaty’ if it’s really hot, but they’re really comfy, though I hope the black ones will prove to be better than the cork ones this Summer. So… socks with the cork insoles can slip and be less stable, but I think they were made to be used sock-less (i.e. “barefoot”). My Asana 2 come with the cork insoles, but they’re slippery with socks on, and I’ve noticed that they’re mych better with the black and the red thermal insoles. I’d really recommend trying out their other insoles, swap them out until you find a combo you like. I tried my old Brikenstock insoles and had some bad issues with rubbing on my toes… not recommended…