Car wanders after Rucas install

[Weedm]

So i just finished installing my spl rucas and when I test drove it, it wandered when I get up to 40mph+.

I bought the part used and it was already adjusted to how I want it, which is 1/2 of an inch longer than stock.

While installing I noticed that a piece was missing from one of the ends, and its the piece circled in red below.



I went on ahead and installed it anyways thinking it wouldnt be much of a problem.

I noticed that my car was raised about 3/4 of an inch now that I have more positive camber. The stock arms had about a -3 camber in the rear with the coils maxed out.

So my question is, what is causing my car to wander? I'm thinking its the missing end piece, or it could be the toe angle, or last case which would be alignment. My rear now has a slight case of toe out and a slighter case of positive camber ._.; all that from 1/2 adjustment to the arms. idk. need help. thank you.