Ive been riding the Flying Brick most of this week too and from work (a 110 mile daily commute) and for local runs into town and just out and about on the Black Isle.. its one of those easy bikes that does everything with a minimum of fuss.. Its comfortable to ride, never misses a beat and takes everything in its stride.
I'd like to smarten it up a bit, a nice paint job would be good, a waterproof seat, a good digital speedo and head unit and maybe some powder coat to the frame and wheels..
I got to looking about for some ideas for a paint job and keep coming back to the BSK Speedworks site, thats where I got the 4 into 1 manifold from and they produce a lot of good kit to upgrade K100's
their cafe racer has the look I am after, but I prefer the riding position I have with scrambler bars and slightly rear set pegs.. I might invest in a set of their rear sets and a shock and progressive springs to stiffen the suspension up a bit.