I was and still am not a fan of longer shackles, it add a bit more degree of side flex to the spring. I like to add a block between the spring and perch instead.
Or better yet, replace the perch with a taller one.
Another trick I use is to add ladder bars with either a shackle or slot on the front of the bar that is attached to the frame. This allows the springs, to cycle
the axle back without binding. You can also fine tune the pinion angle also. It still provides a smooth ride.
I do like the stance you have too! All my cars were sitting a bit higher than stock, but Level. Never cared for the airshock jacked up look.
Here is a picture of one of the cars my wife and I owned when we were younger.
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