Hi I had the same symtoms on my 156 about 18 months ago. Went for the ptfe sprey at first but this didnt last long. Put my car on the ramp and with a solid bar put pressure on all the moving components one at a time. I found play in my lower wish bone bushes, drop links and anti roll bar bushes which was undetectable without the car on the ramp. I decided to change all three on both sides. Put in wish bones with the standard bushes pre fitted (EB Spares) which is a fairly simple job. Had to cut old drop links off as they were properly rusted on,but once off were realy easy to fit (ebay). The anti roll bar bushes are a bit harder as you have to drop the sub frame about 6 inches to get acess but this is more time consuming than dificult as I had to take the exhaust off and strenthening plates. You do have to drill the bush bracket rivets off but that was ok (EB spares). I have had 18 months of squeak free driving and I did notice a difference in handleing but now the squeak is back and I am now regreting not doing the upper wish bones at the same time. Still you live and learn. Hope this helps someone.