The GS911 is a great tool. It will allow you to read codes off of all the boxes, exercise servos, synch throttle bodies, yadda yadda. You need to download the software every time, IIRC (I'm due for that soon), as that ensures you have their latest software. I can't remember if a password is required; I think it is tied to the tool, though.
The MarcParnes stuff is beauty. He makes good stuff.
The clutch job is onerous, but not too difficult so long as you have the equipment to support the bike.
The non-wasser-boxer BMW boxer is really a great motor and easy to work on. Basically, it's not much more than half a VW engine. Hell, some folks have tried to adapt a VW clutch to the thing and I think they made it work. I find it really easy to work on. Mine is a '12 and the valves are the easiest thing to set on any motor I've worked on. Not sure if the '05 is the same.
There is some brilliant engineering on the BMW motorcycles and then there is some absolutely stupid shit. In some cases, it's like they went to the Kluge Kinder Kindergärten and got them to do the engineering. For example, I can't put air in my rear tire at any gas station in the US without a special tool. Had they moved the valve stem a half inch it would be possible. I could rant, but won't. It's a Love/Hate relationship with the bike/dealer/BMWNA.
The final drive, shaft, and swing arm have gone through some permutations in the past 15 years that I can't really relay accurately. You'd think they'd have it down pat but they kept fooling with it, then went from the right side to the left side when they introduced the wasser-boxer.
If the final drive is kaput it is repairable but finicky. It's like any automotive differential where shimming is required to get perfect gear lash. There are guys that do it (one is in New England if memory serves me) if you don't want to tackle it. The input splines can suffer if they have lacked lubrication.
BMW Sport Touring
and BMW Luxury Touring
are both good forums. Both have GS forums and both have snooty BMW folk. BMWLT is owned by the parent company of this forum so you will feel right at home as far as look and feel.
Motorräder. Wir fahren fahren fahren auf der Autobahn. I'd make a joke about Germans, but there is nothing funny about we Germans. If you think otherwise we have a form for you to fill out and line for you to stand in to register your opinion...