the 3 motors are actually pretty similar.
Graupner sport blue 9,5 has a 12mm rotor where as the Gm sport purple has a 12,5mm rotor... other than that they should be identical.
Martin Hofer, Gm driver explains it on the GM brushless thread here on rctech... look for it, there is a ton of other god stuff about Gm motors speedo's etc.
the Brand new GM PRO 9,5 looks to be the BUSINESS if you want the latest in 9,5, but it,s hard to see what they have improved over the 2 others.. ut my guess is it's the same hard ware as a G PRO mod motor but only with 9,5turn can???
but martin can propably tell you more about it...