I just put the 2013 Betty upgrade into my 2600 lumen Betty and it was still a big difference. Some have said it isn't worth is, but seeing is believing to me and I believe it was worth the cost. Considering you can't get a high quality flashlight that puts out the 400+ lumens gained with the upgrade for much less I would say it is money well spent. Unless of course, there is a major gain in led technology very soon and another upgrade kit is released soon!
I swapped my 2600 lumen board and lens into my Betty 1850 lumen and now have 2200 lumen in that. Also a nice gain, though not quite as noticeable to the eye. Still worth it and free.
Betty II 26W 3000 lumen Cree XM-L2/ Betty II 24W 2700 lumen Cree XM-L2/ Wilma 2100 lumen Cree XM-L2 / Wilma "Classic" 1800 lumen Cree XM-L2
9600 lumens of fun!