Complex sentence: It began as a secret project in 2005, first released to the public in 2008, when the model was presented under the name of GTA Concept, and it seems that the first units will begin to be manufactured and delivered to the end of 2010.
Split into simpler sentences: It began as a secret project in 2005, and was first released to the public in 2008 when the model was presented under the name of GTA Concept. The first units will begin to be manufactured and delivered at the end of 2010.