Congrats on the new bike. I just purchased my 03 K1200GT 3 weeks ago. As far as changing oil goes, it's quite easy and straight forward. Just remove the lower fairing (belly pan), keep the screws sorted as a couple of them are of different sizes. I stayed with BMW 20W/50 engine oil and if you buy the BMW filter kit, it comes with new crush gaskets and O-ring. Becareful not to overfill the case. I topped the filter with oil prior to installation. Including the filter oil, the engine took a little over 3.5 qts, just as the manual states, something like 3.7 I believe. Side note, are you still running factory windscreen and seat?