I have a couple of Stihl bars and a Cannon. In the small size all the aftermarket bars are pretty universal so you'll have your choice of them all. Some you can get for Picco chain if you wish, the rest .050 chain. I have two with .25 chain for the smallest nose bars (8mm and 10mm). Used to be they didn't recommend Picco on anything smaller than 12mm (quarter tip) but I'm sure Stihl offers their newest bar in .043 (picco mini). 0.25 spur gears for either saw are $25-30 and are a cinch on the 171 to change. A little harder on the 192 because the clutch/brake are outboard. In 0.25 chain there is an actual carving chain in Stihl- not sure about the others. It helps when plunge cutting- the cutters are shorter so the backside of the cutter isn't pushing against the cut on tight nose bars. I've altered other chains by backcutting the back of the chisel and it helped but might have caused a little vibration because I didn't get them accurate enough. I really like the Cannon bar but they are pricey as well and it doesn't seem to flow oil as well. I'm sure the Oregon sculpter and some of the others are good as well. I know of a few guys with old bars, old chains and old saws that have turned out a lot nicer stuff then I have with my newer stuff. Sorry for the long winded answer.