Here are some.(I really need to get a life and stop saving things like this on my hard-drives)
Reasons-
--They are both very talented.
-They are both thespians.
-They both have a tendency to be a bit intimated by Sharpay.
-Sharpay could even sense that something was going on between them and "ordered," her brother should take Kelsi to prom.(sure she said it was because she wanted Troyella's song, but we all know it's more then that)
-They both conspired behind Sharpay's back in the second movie.
-They have chemistry both on and off stage.
-They both love hats (and are often found matching)
-The little looks they shoot each other, and their non-verbal communication they share.
-We all know who Kelsi wrote those songs for
As for quotes, I'll get back to you.