I just swapped out the factory manual transmission fluid with 1337 kilometers on the odometer (it was definitely a sign). I already did the job on my previous R18, so it was pretty straight forward and only took about 30 minutes. The difference between this job and the previous job was the amount of fluid that came flowing out of the fill hole this time. The car was leveled and it just exploded. Just to give you an idea of how much manual transmission fluid was originally in the car, take a look at the picture below. To be accurate, I isolated the 0.2 quarts of Amsoil I didn't use. Also, notice that the bottles of Amsoil are topped off and there's about 1/3 of MTF in the water bottle.
No more grinds into second and although third is still a bit crunchy, it was a lot better than what I was feeling before.