DiNotte lights are very good. They are high quality lights but also relatively expensive, IMHO.
I have a 200L and a 140R. I also have a Fenix L2D Premium Q5 and a MS900.
a 200L is sufficient for most road riding I do. I also added a Fenix to the helmet and used this combo for 2 years; it worked well for me.
the 300R is 2 of the 140R LEDs. I'm not sure why a 140R owner would sell a 140R to get a 300R. Personally, I'd just get a second 140R that way they can be spaced at different levels or distances. Plus, they run off of the ubiquitous AA battery.
the MS900 puts out more than 400 lumens. People often lowball the MS900, I'm not sure why. My experience is that it's been a very good, reliable light that was an excellent value. I've had mine for a year and have only had battery problems (reduced runtime, and the battery is under recall and should be replaced by Geoman). In reality the MS900 puts out around 600 lumens. The MS900 on high makes both the 200L and the Fenix rarely used.
My advice to you:
1- Get more tail light than you think you need. You'll be glad you did when that car doesn't
hit you. I've had my 140R since Oct. 2007 and haven't had a single problem with it.
2- If you have any left over, some options to consider:
waiting on a MS900 when the battery issue is fixed (Geoman
said he hopes by the end of the month, so possibly within a week or two; $90)
the Sunwayman M40A
flashlight (500 lumens on 4xAA batteries @ $140) or Fenix TK40
(630 lumens on 8xAA batteries @ $155); I have no experience with either, but I like the AA powersource for either
The Jetlite E series A51
($199); I also have no experience with this one, but Jetlites has a good reputation
The above mentioned Fenix ($60)/DiNotte 200L ($100 w/o batteries and charger, on sale) combo that I used for two years. The only reason I moved to the MS900 was because it wasn't quite enough off road in fast group rides with other people using much brighter (and more expensive) set ups. When I was riding by myself off road, this combination was adequate.