Paolo is famous for his vigor and sometimes even ferocious playing, especially when he's playing with a continuo. Here it's a pleasure to see that his sense of balance is so finely tuned. He and Markus play in absolute emotional sync. Very lovely.
An excellent interpretation, full of contrapuntal clarity, richness of ornamentation and well judged tempos, all highlighted by a very well balanced recording which lets you hear every fine detail. Thanks for uploading it!
For the same reason that the other movements sound in F sharp major to you. The performance uses a pitch standard of A = 415 Hz, or thereabouts, approximating the most common chamber pitch of Bach's time. This has become an exceedingly common practice for performances using baroque instruments during the past 50 years or so.
