No, 105 is the middle of the range.
The progression, from lowest to highest end for Shimano is
Sora-Tiagra-105-Ultegra-DuraAce
Sora is 8 speed, Tiagra is 9 speed, and 105 and above are 10 speed from 2006 onwards. 105 was 9 speed before 2006. You don't want to know how much the high end stuff costs.
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http://www.nashbar.com