Interested in this... I do also have an elusive alignment issue after installing my full BMR suspension kit, BMR rear tie rods, and trailing arms. I'm lowered on LG springs and have LG sway bar and endlinks.
To be fair, the issue became noticeable when I upgraded to the LG Z28 20x10F, 20x11R wheels. I think the weight of the wheels and tires may be "stretching" the suspension a bit. I just bought a bumpsteer correction kit today that replaces the front/outer tie rod.
I'm getting deflection under hard acceleration and braking. The car also tends to tramline quite a bit on uneven roads. Tires are 275F and 315R.