I think your option of springs are fine. I'm sure some linear springs would make the comfort level a bit better though. I think you'll enjoy the Steeda Sports as much as the K springs while also improving a bit comfort-wise
There probably won't be much difference in terms of handling capabilities right? I was just thinking in terms of comfort and rough patches of the road. Would the car bounce less? Less jarring? Difference in terms of those types of questions
Any from the years 2005-2009 Mustangs. I'm not 100% sure, but the 10's (v6 included) have 8.8's. Not sure if it's a direct swap though - might need a different flange?