300CE24 front end noise at low speed

I have a 1990 300CE24 that's just had a front lower-arms rplmt done. (Old one was showing signs of cracking rubber and high speed instability ).
Now it makes a clunking noise going over speed bumps, when braking in a straight line and at parking angles. My mechanic regreased the bolts/joints and changed the ecentric bolts. It is still making the noise. Now what? I feel like putting the old ones back now. My high speed instability, I think I solved by putting in 205/60/15 Yokohama A539 tyres (It was shod in 195/65/15 Goodyears before) . Now is handles much better at speed but the low speed clunk is driving me nuts!!!

Corrections to the last message: I had both the fwd lwr arms changed. This was at the advice of my mechanic that the ball-joints were showing excessive play. It was suppose to be a cheap ball-joint rplmt but this set of lwr arms come with integrated ball-joints!!! Tried asking other mechanics and it all pointed to the more expensive lwr arm chg.
The whole idea of the excercise was to enhance the handling/feel of the car. That turned out to be a big dissapointment now with the ever present annoying 'clunk' at low speed, sharp corners like parking the car or slow turns.
I noticed that these sounds do not appear for the first few miles when everything is cool. When things get a bit hotter like after 10-20 miles the 'clunk' will come at almost all slow/sharp turns and even when slowing down in a straight line.