If you are approx 145#, then you're probably not too tall either. In which case, I would suggest to steer away from the WR, for two reasons- It is heavier than the 200EXC and you need a fairly tall inseam to kick the 250 F 4stkers to life. Plus, the 200EXC is a MUCH more dependable starter. The silly 4 strk noise is personal preference thing; some like it, I hate it.
Note about the GG200 and 250, is that they are both about the same weight. The EXC is lighter than the GG200/250, but not a whole bunch.
Depending on where you ride, you might also want to consider a 125 motobike. They are even lighter than a 200EXC and have some real potential after you set them up.