I am categorically against lowing the colonizing cost !! This advance gives a huge boost to the empire development and MUST cost a fortune. I understand why people wants to low it though. In non-conected game you can get really unlucky but, hey, life is not fair !
Even then, computer complex II on the home world let you research 400000 tech in just 25 turns - nothing for non-conected start !
If you still decide to do this, please adjust AI research fules - move colonizer tech up the ladder so AI will research it earlier now, in line with human player priorities.