How has this affected performance (acceleration, braking, handling) of the car? I know heavy 19s will cause performance to suffer, but what about light 19s? I tried to search but to no avail. Thanks.

 

I ran a stock Z on the highway and I pulled on him really hard....don't know if it had anything to do with my wheels or intake? couldn't have helped that much....

As for braking and cornering, I couldn't really tell a difference. But when you're installing you can feel the significant weight difference from stock wheels. plus they look good....

 

Don't get too hung up on the wheel weight. Its the tires that cause the reduction in performance. Why? well, the weight of a rim is spread out from the center of the wheel to the outer diameter. The farther you place weight from the rotating axis, the harder it is to turn. The tire weight is ALL far from the rotating axis, thus and increase in tire weight will have the most dramatic impact on performance.

Bottom line, buy light tires