I think some folks have the wrong idea about the GQ's suspension. The GQ and the Abarth Cabrio have identical suspension's INCLUDING SPRING RATES. Not many realize the Abarth Cabrio and the tin topped Abarth hatchback do NOT have the same springs.
I'm guessing the cabrios use a softer spring because their chassis are less stiff due to the missing metal. Stiffer springs would mean more rattles on these cars.