Be careful what you wish for.... I went the other way due to the car bottoming out from the softer springs. Works much better now with the stiffer springs.
It is actually quite easy to change them out, no spring compressor needed. Check out this thread
Rear Spring Swap?
Of any of the jobs I've done to my car this one had to be the easiest.
Try and watch though because the springs sit down inside the holder a bit and sometimes when the car hits a bump and they compress the side of the coil will scrape on the side of the holder in which case all you have to do is rotate the spring about 90 deg.
Also the new springs that work now are at least 17mm thick (17.50 depending on the thickness of the paint) so keep that in mind. Not sure what my softer springs were but definetly less than that.