[FastPlastic]

I haven't seen any recent posts about the active grill blocks. So you may have to do some searching to find out details on those. I believe one was trying to use a door lock actuator to trigger his when temps reached a specific range. The speed controlled block simply used a spring and air pressure to trigger. As you have found when it comes down to it, testing is ultimately the only way to find out if it's going to do the job. There of course are plenty of other Aero mods that can be done that won't affect engine performance at all. Belly pans, slant backs, and wheel related.