One word of caution on these topboxes. Any amount of weight slung out back of the scoot will have an effect on handling and stability. On both my Super 9 and the Yager 200, the weight out back can cause a wobble at the handlebars at certain speeds. Both scoots are so stable without the topbox weight, you can take your hands off the bars and they will usually track straight perfectly. There is nothing wrong with the steering head bearings or tire pressures.
On the Yager I use the Givi rack with a medium-sized box on top. Both seem light enough, but loaded up they will definately affect the balance and handling.
Wil B.
Broadview, IL
'71 Guzzi Ambassador
'91 Nighthawk
'04 Kymco Super 9
'10 Yager 200gt