I say go for it. Being a cut song from the movie, the odds of a lot of people singing it are pretty slim in my opinion, and if you're comfortable and it shows off your voice, then I definitely think you should stick with it.
Honestly, I do hear a *ton* of Wicked at auditions, but nowhere near as much Hairspray. In fact, I wouldn't even put Hairspray in the top 3 shows that are oversung at auditions (at least in my area). Wicked, Les Mis & Thoroughly Modern Millie are the ones I hear over an over.
So all that so say, I think you're pretty safe.