S!
As Jan stated "Data is taken directly from charts in HTC's homepages so they might not represent 100% accurately performance of planes in AH".
I think HTC hasn't updated its charts after HTC's D-30 wep update and by that nor Jan. There are differences between P-47's, but not so significant. With WEP D-30 is fastest then D-11 and D-25. If you look SL speeds from HTC charts it states that D-11 is fastest and then D-30 and D-25. With that 300hp wep boost D-30 had, it should be the fastest, but as I've said before, I haven't re-tested them after update.