I rebuilt a little Husqvarna this winter and decided to set it up with .325 narrow kerf bar and chain to see if there was much difference. I have been cutting my own firewood for years using mostly 50cc and smaller Stihl saws with .325 .063 chain which is (or was) Stihl's standard. I got a Husqvarna X-force XF250 bar and loops of Oregon 95TXL, Husky SP33g and Stihl 23RS (previously called 23RSPro). The Oregon and Husky chains are semi-chisel and have extra bumpers on the rakers. The Stihl chain is straight-up full chisel. The Husky chain is marketed as low kickback ("safety") chain. The Oregon and Stihl chains are marketed as non-safety chains. As far as I know, Stihl is not marketing the 23RS as NK chain, but it compares well with the Oregon and Husky flavors that are sold as NK.
T-B and L-R: 95TXL, SP33G, 23RSPro, and 26RS Stihl .063 chain for comparison.
The 23RS is much narrower overall than the 26RS- about .020" as you would expect. The cutters are also narrower, but longer than the Oregon and Husky offerings.