Originally Posted by gagliano
So then a dual adjustable coil over doesn't need all the travel of a single adjustable coil over to make ride height adjustments?
The real, actual point is that ride height is not adjustable
. You can adjust it a bit, but with a decent suspension design (and i'm talking about the suspension links, here) there is very little room to adjust it in either direction. Therefore, good coilovers simply adjust the length of the strut to match the correct ride height, and give you adjustable spring perches for corner balancing and setting wedge.
Look at the RCE springs for the 08+ cars for an example. High performance lowering spring that drops the car less than half an inch. That's all you can get away with on the new cars.
Dual height adjustability simply means they didn't bother designing a damper for a specific car - they just use one damper for a million applications. It's cheaper for them, and thus they make more money. It's not a performance feature.