The Tarett arms are adjustable for roll center on the ball joint side as well as camber and caster. Camber is adjustable via shims at the chassis end of the arm just like the Porsche factory cup car parts. In fact, the same shims are used.
The caster and wheelbase is adjustable via this red eccentric that the tension rod in the front and the trailing arm in the rear bolt to. The arm pivots on spherical bearings eliminating all rubber that can flex and cause the alignment to deflect and to cause rubber feeling and slow response.
These are the shims used to adjust camber by spacing out the lower arm between the man body of the arm and the spherical bearing inner pivot.
We replaced the OEM front suspension tension rod and rear suspension trailing arm with these adjustable spherical pieces from Tarett Engineering. The Tarett parts give full adjustability for the caster int the front of the car and wheelbase in the rear. You can also adjust the anti-squat and anti-dive to a degree, something that is not often exploited and should be considered in a lowered car.
A spherical bearing is used at the chassis end of the of the Tarett arms. You can see the spacers and washers that you can stack to adjust the anti-squat and anti-dive by moving the bearing up and down. The stock front tension and rear trailing arms also use a spherical bearing but when going to a lot of negative camber the wheel goes forward in the wheel well and the adjustable length lets you center it again. The tension arms also give the ability to adjust caster precisely.