if you have 26mm (which I do on both of my cars) be very specific on what you buy because the 26mm rotors were produced for only one year so regular autoparts places become stupid trying to find them in their catalog. and if you get 30mm rotors with 26mm calipers you will be sad. Been there done that.

Switching gears 26mm rotors have 3mm vented center section and 30mm have 7/8mm vented section which the 26mm rotors are prone to cracking if you drive very aggressive or extreme temp changes (IE. hard braking in a puddle) Honestly go with the 30mm they are more reliable and the clearance from the caliper to wheel is only 2mm difference (checked on S14 SE rims with both calipers) Hope this helps you.
-Dave