I switched my stock Pista's fork/headset/stem. It wasn't too much of a big deal (though I did opt for some pricey parts). I got a threaded fork from Spicer Cycles, a new headset (Chris King Grip-nut) and a couple different stems. I've got the Nitto Jaguar for my B123AA bars, and a Nitto Pearl for my RB21s. Makes changing bars easier than a threadless setup when all you do is swap stems.