I have used the14m in a range of conditions, it excels at the lower range and I found has a large overlap of "usability" with the 17m - it is closer in feel to the 17m as a lightwind kite with upper range, but I would not use it over the 12m in constant 20-25knts.
Bar pressure - you're asking the wrong person, I come from the Pumping Iron spectrum of preference - it is fine for me and both the 17m & 14m loop nicely.
As mentioned the low end is very good, providing you are on the right board - the 14m powers a Sector 54 along (& my 95kgs), when no one else can move. In the upper wind ranges, the kite unlocks great hangtime when everyone else can barely move.
Turning speed - medium to ok/adequate for a 14m
Windrange - for you....no idea (as it depends on so many variables... weight/experience/conditions/preferences) - for me on a range of boards (Sector 54/SB's & Mutant) and bearing in mind I use the 17m in low wind - 18 to 23 knots ideally.
Hope that helps