I have the Ricochet skids and there is no issue with the URD headers clearing them.
As said before the URD's are difficult to install. I didn't have to lift the engine to get them in. I only had to disconnect the steering shaft, and used a stud puller to remove the rear-most manifold studs on the head so they can slip on. (reinstall them later) I think it took me around 10hrs to do the install. The real fun part is tightening the nuts, and you will need to re-check them a couple times because they will come loose. I highly recommend getting some long flex-head, ratcheting box end wrenches, and universal joint style flex sockets before even attempting to do the install. Use new OEM gaskets, and you need to apply high-temp RTV the gaskets to ensure a good seal.
Regarding the Y pipe.. I don't think it really matters which one you use. If you delete the secondary cats along with the headers you are looking at a significant sound increase, and it's not a good sound. As you can hear in the clips above anything above 1/2 throttle and you will get that farty raspy sound along with a bunch of drone unless you have the cats or a substantial muffler in place. Maybe you're ok with this? I tried 3 muffler setups before I got the sound to what I would consider an acceptable level/tone. It's still aggressive sounding but without a lot of the rasp & grossness. I settled on the following: URD headers > DT Y-pipe > Large Vibrant resonator > Flowmaster Super 50 > Small Vibrant resonator > Tail pipe.