tip from el jefe
Providing your factory original allen head banjo bolt is in decent condition, grab a pick or small screwdriver and scrape out all the shit inside the recess, the allen key MUST go in deep...if there's crud in there, she won't go in fully flush, you'll strip it, and you'll regret ever starting this job.
Grab a can of your favorite brake cleaner, take the cigarette from your mouth and lie it across the cross member on the opposite side, and blast a nice stream right into the hole. Now she's clean. Clean around the bolt too since you don't want a spec of dirt anywhere near that bolt.
Insert your 6m allen key wrench into the recess and gently tap it with a hammer to make sure it's fully home. Now grab a 13mm combo wrench and slip the closed end over the key so that the box end is above it closer to the oil pan. The combo wrench will give you leverage and torque...your two friends in this juncture. Now gently apply downward pressure (loosen) and it should abruptly break free.
When you're done doing the hokey-pokey with the return line and ready to re-insert the banjo bolt with new 12 x 15,5 copper crush washers part number 900 123 026 20 (one on each side), you'll do the reverse sequence with the allen key/combo wrench this time the combo wrench will face downward so that you can apply upward pressure. Tighten, but not the kind of tightness to make you fart...just tight. And there you have it...fetch yourself a beer and enjoy the money you saved.
In case you're wondering, there is an updated six-point banjo bolt to make the stripping woes go away, but you'll have to buy it used since I bought the last new one in the country from Porsche. I ended up getting a spare used one from Parts Heaven...just in case.