Froze, to summarize in case it helps you:
111 = 111D + DVD-RAM
111L = 111D + DVD-RAM + DVD+R SL auto bitsetting + LabelFlash
So the 111L (Buffalo firmware) has all of the features of the other models plus some exclusive ones, that's why everybody recommends flashing to 111L (maybe the only disadvantage, reported in several posts and that I think I have also experienced, is that with 111L firmware the drive is noisier). Additionally, as you will use TDB firmware to crossflash (flash to a different model) your 111D, you will turn it into a RPC1 drive (the drive's internal region-change counter will be removed; realize that, as stated on TDB website, to be totally region-free you will still have the OS and the software counters to defeat).
About bitsetting, I think it can't be done manually, as Justin42 says, and that none of the models can do it with DVD+RW. Bhairav, are you sure you can bitset DVD+RW?. Do you think you could find out and confirm it?.