Narrower tires does not equal faster speed - especially for a small wheeled bike. The passive suspension offered by the Kojaks [assuming you pump them to allow for 3-5mm vertical drop when you are on bike] will reduce rolling resistance compared to a smaller volume tire at higher pressure.
honestly i am not the type of person who wants shock absorber on my bike. i don't like big apple at all even if it will make my ride comfy. in fact i've been wanting to change the big apple on my Curve. i always pumped my tires higher pressure and love it that way. i like it when i can feel the tire runs over the pebbles. so yes for my new setup (kojaks vs big apple) on my TR i can say that i can feel it a little bit faster. since it's almost winter now i might go back and change it to a schwalbe 20x1.5. anyone has experience with kojaks for winter riding ? do i need to really change my tires to regular ones or this will suffice ?