Fastest commuter bike for under $400?

I am looking for the overall fastest commuter bike under $400. The maximum toughness needed is for going up and down curbs (at slow speeds). I am currently looking at the Mongoose Crossway 450 (http://www.mongoose.com/mtn/ProductDetails.html?id=2648&enc=mtn|) and the Trek 7000 (http://www.trekbikes.com/us/en/bikes/bike_path/hybrid/7000/). If anyone knows which of these two would be faster or if you know of a faster bike than either of these under $400, I would love to hear from you. Thanks!