As emmanuel.yoo has contributed another formal drag slip [
http://x3.xbimmers.com/forums/showthread.php?t=1508670 ], I'm updating the spreadsheet and also plotting it against the stock and hypothetical X3 M's with varying HP. His data lands almost exactly on the 400 HP curve.
Will be interesting to see slips from tracks which also provide 1000' data to enable full split times analysis, as well as a formal slip for a '100% stock run' to serve as a reference with which to compare various modifications.