Buffer underrun protection works when the drive stops burning, waits for the data to catch up, and the resumes. But because it stopped, it has to remember exactly where it was before. And sometimes, its positioning can be a little bit off when it resumes, which might cause problems. In my experience, though, buffer underruns don't seem to have too significant of an effect on quality, though results may vary from drive to drive.
The process should be fairly safe, as a number of people have done this before. Use LtnFW to load the UYS1 firmware into your drive. It's a LiteOn drive, so even if something disastrous happens, you can probably recover your drive.
However, as with the use of any unofficial firmware, doing so will void your warranty.