I.R.S. may sound pretty enjoyable, but IMHO, overall is not a strong song. Chinese Democracy also isn't good. But I voted for IRS, just because CD has some potencial to be pretty nice song and maybe it will, in the very final version. Even if the album version will not be good, i think, gunners will really improve it during the live shows
Unfortunately, i don't see in which aspect IRS can be improved, maybe solo, but i don't think that would change the song hardly.