Over the past couple days I installed my Xecuter 2.3Pro, flashed the BIOS and installed EVOX. It's been my impression from reading the forums that you should NOT use CDRs but I have had no problems with this. My CDR media is KHypermedia, 700MB and i'm using NERO (my CDR brand is some generic brand I got free with a rebate or something like that). My Xbox is v1.3 with a Samsung DVD drive. I've flashed via CD, X2BM, and via CD again. It all works. No problem with the EVOX iso either. Now that I can FTP in to my box I'm all set.
Don't have a DVD burner, didn't want to by any CDRW with the hundreds of cheap CDRs I have around... so FYI, CDR is working just find.