Can someone clarify something: I have a 111D crossflashed to a 111L with 8.29 firmware. In your opinion the burning quality with 8.29 firmware is the same if i use 111D, 111 or 111L or there is a “better quality” model?
Thank you. 
I personally don’t think that the quality can differ drastically. Even if it were different among 111, 111D and 111L, the last, IMO, would be the winner 
But there is another thing. On the manufacturing stage Pioneer Corp. can verify the quality of the production and, for example, the drives with DVD-RAM writing deffects offer to the consumers not as 111, but as 111D.
I don’t know that for sure, of course, but remembering the practice of such companies as Intel and AMD… :a
And the firmware related writing quality can only change from version to version, IMO.
No write strats were obviously changed, so the difference could only be marginal.