This was on a series IV 144, but I clipped my track for this season, and beyond the cost, there's nothing to lose. It feels like the track spins more freely, and we'll have to see, but I bet the hi-fax lasts longer too. Just one season with the track unclipped caused quite a bit of wear. I used Camso flat clips and Woody's track tool (couldn't find the perforated clips in stock), and it was pretty simple. I'd already cut the windows; a sharp utility knife is all you need for that. You gain a little weight and rotating mass (probably very little over an un-windowed track), but the lower friction makes up for it. The shorter the track, the more it does for you: you need track speed, and I think the 1-2lb you add in track clips is more than made up in track speed.