Yes you can mount a spoiler on your car, any exterior body part from any 05-08 corolla can mount up on yours correctly.
If you want to make your corolla look a bit better, you can find the OEM "S" Lip kit, make sure its the 05-08, not sure if the 03-04 "S" lip kit would go on, I'm sure the 03-04 front lips won't go on because they changed the front bumper cover in '05. You can also change your headlights with the 05-08 S headlights or the 05-06 XRS headlights, it would give it more of a sportier look.
Guys please correct me if i am wrong! :facepalm: :thumbsup: