afaik the problems that occured when burning with nero were not in 'iso writing mode' but in 'DVD video' mode, where you just supply all the vobs and nero would do the rest... but i'm not sure as i'm always creating isos with imgtool classic and burn them with DVDdecrypter... if tried burning isos with Nero twice, just out of curiosity to a RW and it worked like a charm and even a bit faster than with DVDdecrypter... anyway, i'd suggest you first try with RWs and then go for Rs... this way you can't really screw up :) steVe