Just a FWIW you do not need to use QA-1/Carrera springs when you replace them other less expensive springs work just fine and are just as good...stay away from the Chinese crap though...
As Jack said for the weight of your car 165-185 lb spring rate should be fine and will loosen up your ride. Regarding weight it really helps to weigh your car...you'll want frontend weight, rearend weight, and overall weight with you and a passenger, full fuel tank, once you know those weights it is relatively easy to find the correct weight of spring needed.

Start your adjustment of the knob on the shock at the lowest rate, drive, then adjust until you get the type of handling you want.