Two things I added/used on my XTown 300i that I think have adverse effect on handling---on high crowned country roads-----my E-46 Givi box---maybe too wide and heavy, replaced by narrow, $40 Bestem Box=improved feeling---load 8.5 pound dog. Equals better running on the mentioned roads.
And Puig big touring screen, cut 4 inches with Laminar Lip added---hopefully to push air over head. Maybe being wide and much more area than standard gives some input to straight line running. So standard shield back on with Laminar Lip---running feeling much better. On my 11th Maxi scooter since 1990=there is no way to achieve really quiet air management, simply because of distance from tip of nose to tip of shield, period.....and of course for safety looking over shield. Vespa with right shield/right height does manage air well. For me, doing this for 65 years, great air management makes 8-10 hour days on road more comfortable. My usual reason for daily stop on trips....is at about 400 miles my ear channels become a little painful from foam plugs......and of course at 81 I am getting a little tired at this point. I think at this point 250 mile days are better----but sometimes I just want to get there!
At this point, near 10,000 miles, I am happy with my XTown, realizing there is a lot of bang for the buck. Does everything my Suzuki Burgman 400's did at about half the price.....all are too heavy, Kymco much easier to work on than Burgman.