Complex sentence: In 2003 Takara decided to test "Microman" market with brand new but small series called "Microman 2003" which was aimed more towards the collectors and older fans.
Split into simpler sentences: In 2003 Takara decided to test "Microman" market with brand new but small series called "Microman" 2003. This time the line aimed more towards the collectors and older fans.