Well at the moment I'm still running the stock RCD300 head unit, so I'm withholding final judgement until I've put something of appropriate quality in, but the sound is remarkably improved already.
The crossover is set to attenuate the tweeter -3db, while the mid is set to the middle level.
Bass is phenomenal, mids are well balanced, but the treble is a bit bright though I'm not sure if the head unit is to blame.
I would consider them a fair step up from things like the Hertz hi energy stuff, and for £200 I simply had to buy them!!!