Never done them myself fella, but sent a pair away about a year or so ago, he was fab, good pricing and top quality..but think he may have gone out of business or re-located..
i used to run GA cycles in southampton, Gary the owner is absolutely poo hot with them, but they can be big money to service and i wouldn't recommend taking one appart if you don't have the tools or skill or training, they can turn into a jigsaw puzzle with no picture, in the dark while you are blindfolded and handcuffed.
i know people still send them to him but depending on the problems depends on how long it takes.
the other option is TF tuned are now officially doing them i think.