They just tested the "maxed out" 11" and 13" models.
http://www.macworld.com/article/155224/2010/10/macbookairbto_benchmarks.html
The 13" 2.13GHz model tests about 10% faster than the 1.86GHz.
http://www.macworld.com/article/155224/2010/10/macbookairbto_benchmarks.html
The 13" 2.13GHz model tests about 10% faster than the 1.86GHz.