I put a pair of these led crees in my side lights (2011 RT TC) http://www.ebay.co.uk/itm/291153851050
Very pleased with them. No canbus faults and very bright.
The best way to access them is to remove the mirror. This is easy to do, on the underside of the mirror housing is a hole. Insert a torx key ( I think the right size is in the tool kit) through the hole and slacken the torx screw. The glass can then be pulled out giving access to the torx screws that allow the mirror housing to be removed.
The Haynes manual has some good pics of how to do this.
Hope that helps,
Phil.