Crank chainring options

[yeboabe]

Looking to change my cranks to 2x9 (9x2)

 

Have M970 XTR and Truvativ Stylo's

 

So would like to know, who makes a chainring for the above for a 40/28 setup for the above and what else do i have to consider?

 

[_Daemon_]

You need Specialties chainrings. But it's hard to find.