Just to let you into some invaluble information, i've recenty fitted powerflex ( www.powerflex.co.uk )bushes to the front lower wishbones on my 156 2.5 V6 (heavy engine). I've only fitted the rear of the two bushes as it was only the rear one that had worn. The results of this is that the old bush must of lowered the car and with the new bushes i no long ground myself going over speed bumps. Also the feedback from the steering wheel, is alot better. It's an easy to average task to complete if you anyway mechanically minded, but if your unsure a local garage shouldn't have to much trouble. If you only had £100 to spend on your car then i would buy a set of powerflex bushes.
To answer both questions, to find out if the bushes are worn i'm not sure but what i have noticed is that there is less clonking noise from the front wheels and the car feels more confident going around corners. Also i dont ground myself going over speed bumps.
I dont think the word harsh is the word, more that you are aware thet the road is rough.
Hope of some use.
At the end of the day its cheaper than changing the wishbones.