As you can see, the RS is the fastest followed by the basic nacked K100 and the RT comes last (certainly due to the weight rather than the aerodynamic).

Interesting to see the difference between the naked K100 and the RS.
I would have guessed it to be a greater difference in top speed.
What I`ve noticed is that my RS seemes to get more stabel at 180 km/h than at 130.
The pressure on the fairing seemes to push the bike downwards,maybe that`s just imagination but I can`t describe it better.
Over 180,moving the bike from right to left as in an overtaking manouver craves more force as handling gets more sluggish at high speed.
I don`t normaly ride at those kind of speeds but it`s fun once in a while to squeese the throttle.
I`ve seen 270 km/h on the clock of a K1 that I hade the pleasure to try out back in -89 and it was rock steady.
Same engine as the K100 I belive but with paralever swingarm,stiffer suspension and scientific areodynamics.
Cheers,Wikur!

I personally find that the RT has a better handling with a passenger.
I push the bike once to 200km/h. Up to 160, it was very good. After this, the quality of the handling started to degrade and when I reached 200 it was scary. I don't know if the bike would go faster, but I got scared and slowed down.
When I was younger (in the late 70s) I had pushed Italian bikes (Ducati 990ss, Laverda1200 and Guzzi 1000 Le Mans) up to 230 and the experience was like riding on a rail. These bikes were sport bikes with small fairing and I thing this made the whole difference. The RT fairing is huge and any side wind will alter the handling.