AEV will have a ~2" spring lift (as opposed to the spacer lift you linked to) out this summer sometime. The news of the spring lift with the caveat about release date is also on the AEV site.
In case you are not familiar with the differences between spacer and spring lifts, the spring lift will give more articulation to the susension, both in compression and rebound. Good for keeping the tires on the ground and also for adding more room for the suspension to work on rough terrain and so improving ride by keeping off the bump stops. Also, given the fantastic ride and handling of the other AEV spring lifts, I'd bet that the ride and handling are better than stock.
EDIT: I read your Newb post, and obviously you know the difference between spring and spacer lifts, so disregard the previuos paragraph! I have the AEV 4.5" suspension, its great, you'll love it. You will need new gear to run 37's. I'd suggest 5.13's, maybe 5.38's with the trailer towing. I run 4.88's but have AEV's Hemi in my Jeep. Even with the Hemi I sometimes think 5.13's would be better.
I have an M101A2 modified by the military by installation of the A3 drop axle, it has the Huvee eight lug, eight bolt wheels - without beadlock insert - and military 37x12.5x16.5 Wranglers. Perfect height for the AEV 4.5" suspension, drawbar is dead level. I also have an A1. Great trailers. Many think they're too big, but I think they go really well with a JKU.
JPK