I had some info in my head a while and with some posts from other threads recently, I think I have a good enough grasp to share my view.
Front and rear track to adjust handling.
When I installed my teins, I also did my 25mm rear spacer atthe same time. At the time I thought the 25 mm spacer, made the front and rear track the same. The lookedclose visualy, but recently someone found they make the track 10 m wider. This doesn't sound like much, but from my experience it really effects the car.
http://alltrac.net/phpBB2/viewtopic.php?t=9661
I had a 8mm spacer that I bought to make the fronts look better since they were so tucked, even thought it didn't help my 17x7 40ets much, it did change handling a bit.
At first with just the 25 mm spacer the car handled well. There was minor push going into a turn, nuetral middle turn and slight oversteer on exit.
I tried driving the car with the 8 mm spacer on both fron and rear.
On the rear the car had simular characterstics to w/o the spacer but I had to turn up the rear struts to maintsain the slight oversteer on exit.
Instaling the 8 mm spacer on the front made the car scary. It made the car into point and go. I took some turns so much faster that it firghtened me cause I was used to being at the end of my limits at that point but now I still had grip. I however didn't notice the oversteer qualities much cause the car seemed to rely more on hte fronts to do the work and dragged me around.
I am not sure if a 5 mm spacer would be better for the sake of making the tracks even or the 8mm spacer since the front track is slightly wider than the rear. Maybe the best way to test is someone with 20mm rear spacers to test even track and then adding spacer on the front to see if it improves handling or not.