you cna use EITHER axles from a 90-93 integra OR a DC2+integra/99-00 SI. heres the catch:

90-93 axles will slide right into a CABLE B series gearbox and you use the 90-93 HALFSHAFT. if you want to use the 99-00si/DC2 axles, you must use THEIR halfshaft, and the tranny must use the corresponding axle seals.

Basically you run the axles that correspond to the tranny and halfshaft.

IE
If you have a S1,J1, Y1, YS1 CABLE B series tranny, the 90-93integra axles will work fine, use 90-93 integra halfshaft

If you converted your car to HYDRO, you use the DC2/99-00SI axles with DC2/99-00 HALFSHAFT

If you want to run DC2/99-00SI axles in your CABLE B series gearbox, you need to buy the AXLE seals from a 94+integra an swithc them out

Also, the 94+DC2/99-00SI HALFSHAFT is a FEMALE halfshaft, where the 90-93 HALFSHAFT is a MALE halfshaft.

I run DC2 axles in my EF with a HYDRO tranny