Product: Pedders 2954 and 2955 springs, advertised 20mm front lowering and 15mm rear lowering.
Result: ride is firmer as expected, car is lowered -2mm in front, 10mm in rear. If you want to make the suspension stiffer while not lowering the front at all and slightly lowering the rear, this is a good product. It's pretty clear that it was designed for a G8 / VE and the advertised change in ride height is from G8 base suspension and not the FE3 package shipped on the SS.
Result: ride is firmer as expected, car is lowered -2mm in front, 10mm in rear. If you want to make the suspension stiffer while not lowering the front at all and slightly lowering the rear, this is a good product. It's pretty clear that it was designed for a G8 / VE and the advertised change in ride height is from G8 base suspension and not the FE3 package shipped on the SS.