The advantage of having your driving lights on a relay is that you will never accidently leave your lights on when you turn your scooter off. Otherwise, your new lights will turn off when the scooters ignition key is turned off.
The relay has NO
effect (drop) on the amount of voltage/amps that goes to the lights from the battery.
I always recommend using a fuse and a relay when installing any new lights (55 Watt Driving Lights) that draw power directly from the scooters battery. If you plan on tapping power off a stock Honda power wire (tail light) that powers a stock scooter light to power your lower voltage/amp drawing accessory lights, then your OK. These Honda factory power wires are already on the scooters relay system.
The relay I recommend is not allot of money and works well for installing front driving lights. I always provide a simple wiring diagram for relay installation on a Light Bar installation.
Here is a Relay that will work for your new driving lights: http://cgi.ebay.com/Relay-and-Socket-12V-12-Volt-SPDT-30-40-AMP_W0QQitemZ200396098915QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2ea889cd63
Here's a picture of the relay installed: