I don't think I'd use regular spax with GCs. I'd go koni, spax adjustable, or bilstein. They're find with my roush springs and stay strong when pushed. I imagine with stock springs, ride would be about stock feeling. Any ride harshness comes from the lowering springs. They've got a better ride than blown svt struts.
I don't know if they're rebuildable,etc. Konis aren't the only right strut for lowering. It depends on what you want. How low are you going, track use, need adjustability,etc.? The regular spax are fine for my needs and are doing great.
