Most of the time once you change your suspension you will notice a problem or two, most of the time its the improper tightening of the front struts.
This happened with me a few times since I had various setups with the solara.
If you noticed that your struts have a 'notch' on the top of them, and the strut mount also has this same notch (where they have taken a circle & flatened off the 2 sides) you know what I'm talking about. I have sketched up a ghetto picture below.

Basically, you tightened the 19mm nut when the strut mount & strut were not seated properly 'inside' each other. Try loosening up the nut a bit, driving around a little till you dont hear it, then tighten it back up Or you can remove the front strut assembly and redo (I considered the fronts easier then the rears since its pretty easy to do it by yourself.