Its all to do with the panhard rod type rear suspension set up.
to refer to my (rough and ready) paint diagram
Now, the panhard rod stops the rear of the car from wobbling about all over the place, but, because of it, in order for the suspension to move up and down, it must also move from side to side.
basically if distance A gets smaller, the angle at Z also does. because the hypotenuse of the triangle cannot get any smaller, the axle has to move to the left.
As it does so,allowed by the flex in the trailing arm bushes, the wheels must also turn slightly, so the front of the wheels are pointing towards the right slightly.
You may notice this in reverse, when you jack the rear wheels both off the ground, the angle Z gets bigger, the axle moves to the right.
Now, for a standard car, volvo obviously set it up so that with an average load, the wheels were pointing straight ahead, and the front tracking can be set in respect of this.
But, for a lowered car, the panhard rod/axle are always in the "compressed suspension" position resulting in the wheels pointing a little off, and the car turning left. In addition to this, if the tracking is done with the car lowered, the lasers pointing of the rear wheels will ain to teh right (looking from rear of car) so the tracking will be set with this error included, resulting in the car crabbing slightly.
My car handles beautifully with the 40mm drop, and it only pulls to the left slightly, so I am going to continue with it, also i can't see any way around it. Just thought it might make mildy interesting reading, and someone might have an idea.
One idea maybe, make the panhard rod shorter, but this would require some fairly accurate measurements and welding.......
