In my case, the awning will. Drop-in RR's for our Xterras are redonkulously expensive.
If you're looking for drop-in rack, and you're ever in Arizona, there's a guy out there who makes his own. They look to be great quality and the price is great. Alot of the AZXC guys run his drop-in model, and I think they're about $200. Again, if you're ever out that way, you'll avoid the shipping, too, which is a major piece of the cost of ordering one.
That said, a drop-in rack doesn't exactly make it easier to mount an awning. In some cases, it could actually make it harder or not possible at all (if you're using a muffler clamp or other tube clamp style option). For now, with a stock rack, the muffler clamp/L bracket option above is probably your least expensive and easiest route. If you can get your hands on some of the Yakima X-tower mounts, this will be a much easier job. Those mounts are harder and harder to find now that they've been out of production for a few years, and they're usually pretty expensive when you do find them. You'll need at least two of them (obviously), and maybe even three or more depending on the length of your awning.