jaxgtr

Yes they are. I started to swap them out for the Pro 3V's on my Domane with those, but I ultimately wanted the Pro 51's. The wheels are really nice with the DT Swiss internals. I would talk to your Trek dealer and see if they can get the Pro 51's now. I was being told Feb as well and about 3 weeks ago, they had some Pro 51's in the Wisconsin warehouse available for order, so I did. They are suppose to be delivered just before Thanksgiving. If I waited for the NJ warehouse to get some, which supplies Florida, it was Feb or March.

I like the 37 depth, but having the better aero dynamics of the deeper wheels is what I wanted, and also wanted a slightly narrower internal width so the profile of the 28's would be a little less square compared to running them on the Pro 3v's. Those things are so damn wide at 25mm internal. The Pro 51 is only 2mm wider than the Pro 37, so not a huge different. 23 versus 21. You can pretty much install most anything on these, but limited by your frame. A guy at the LBS but a 40 on the Pro 37 and it worked, but was really right on the rear triangle.

guachi

I have a set of Pro 3V wheels as stock on my Domane as well as a set of RSL 51 wheels and the 51s aren't noticeably faster. So my recommendation is to get whichever of the Pro 37 or Pro 51 you can get sooner. Though the 51mm rims look cooler.