My sax is being lowered on wednesday

dropping by 40mm with the torsion bar to match...
How good are these springs? as im only lowering by 40mm I decided not to get a full kit inc dampers etc but was this a good move lol, and finally how much is the ride and handling compromised?
Ive heard that if your not going lower than 40mm, theres not too much to worry about as the height adjustment doesnt put that much stress on the orignal parts so hopefully everything should be fine
Only wondering as my mate had his sax dropped 60mm and had a lot of driveshaft probs, hes since had it raised
cheers for the help peeps