Interesting I went to a 15lb lefty singlespeed for a challenge then after a few years found municycling and haven’t got on a bike since so same as you 
5.4kg kh26 build here
Went for a short ride and it is so different and it is effecting my general stablity. Not sure if it is the rounder tyre or the wider stance on higher q factor cranks hmm
I will adapt I am sure but it does feel light beneath me and I can easily smack it into my arse doing seat in hops so I need to work on my technique more to go higher lol
Tyre grips well although squeeks which is probably the mold release film on the new tyre so that should wear off.
Cranks feel wide and I will measure the difference tomorrow to see if it is more in my mind.
Saddle is very comfy and very stiff worth the effort of fitting it.
As for the new wheel I like the exceed nice strong flanges I am happy pulling bearings so don’t care about that “feature” and the pure ti design looks sweet. We will see municycle.de have them 
Overall I am happy although I didn’t expect it to hit my rifing this much as I am used to hopping between 3 different unis.