Stems are easy. I was a bit intimidated the first time I started to mess with threadless but once you see how it all comes together (preloading with the top cap), it isn't a problem. Spacers can go above or below the stem and, depending on the clamp height, you may need more, less or different width spacers (easy to get at the LBS). There are 4 measurements on threadless stems: steerer clamp size, bar clamp size, angle and length. Steerer and bar clamps need to match what you have, angle and length are up to you. Go for it (and that's a nice looking bike).