Not sure where causian asian got that info but its not correct.
The SPK 85 and 75 are basic versions of the SPK 90. This year the SPK is the 100 flex, but the 90 from last season is basically the same boot with a softer flex and the older buckles.
The 85 and 75 have none of the features which make the SPK 90 or 100 great. They dont have the Goo toe, the soft spoiler, the gel heel cushioning or a heat mold liner. So really its just a super basic wide fitting boot.
If you want all the best parts of the SPK you need to get last years 90's or just get this years 100's which also have the updated buckles.