Do you know what the current springs are? Most are 40mm drop anyway with the occasional 30 so if they are cut down from that a set of 40mm springs are likely to be less of a drop and actually softer as they get stiffer when cut down. Having said that if it's a bouncy ride that wouldn't be a bad thing, the springs as is are probably too harsh for what are probably standard shocks ( uprated shocks are much harder to get and more expensive than the springs for a Panda) so a set of uncut springs, preferably with fresh shocks would improve things.