Recently got an '18 twin rail, elevated before I ever rode it (had bent rails when I bought it). It's a real treat. Runs very well (Silber tune & a Bikeman Y-pipe), and the chassis just flat works. I hopped on a well setup '16 (clutching, timing, y-pipe, 8T driver) after riding the '18 for most of the day, and just about went over the bars when the low end wasn't there. That '16 is like an on/off switch where the ctec is very linear. No doubt I can do more, more easily, on the '18. On the other end of the spectrum, going between the '18 and an alpha, I'm not blown away by the difference. Could be setup there somewhat, tough to say, but I don't regret not ponying up the extra cash for the single rail. I'd have bought a '19 twin rail for the updates over the '18 but ended up with a good deal on the '18 and it just made financial sense.