Does it help at all? How often it stutters with and without PSM? I'd like to understand this a bit better to know if anything can be done about it. If I've understood it correctly the stuttering happens because of scanning of WLAN access points?
I'm not sure. If it's the automatic scanning of WLANs that's causing it, that won't help. But there is a value in gconf that you might try to change: /system/osso/connectivity/network_type/search_interval By default it is 300, which I guess is in seconds (5 minutes). Does this match the interval with stuttering bluetooth? You could try changing it if so. If that helps, it's easy to make Custom Action to ProfileMatic to change that upon some conditions.