IN 2005 to 2007 DRL could be set on or off by any qualified dealer. It requires a program change in one of the electronic modules.
So it is an "option" but not "user serviceable".
A dealer will probably do it for you at no cost if you have the car in for something else... but will probably charge you something if thats the only reason you take your car in. -John
P.S. DRL will cost you 0.5 MPG during city drives, as the power draw will reduce EV time...