I raced with the GT2 front arms on my T4 this past weekend. No changes in geometry observed and no issues with breaking them. Our 2WD class was a hack fest this past weekend too. One thing I like is the lack of spacers on the outer hinge pins, makes installing them even faster, and what's interesting is the tab that the shock mounts to is single on the GT2 arm, but double on the stock T4 arm. I'm not sure if there is a strength difference between the GT2 arm and the T4 plastic arm either. I used the GT2 outer pin, it worked fine.