In the vanilla game, razing a city immediately avoids any penalty to science, but in VP, it increases the cost of techs. I presume that's intended, but it does seem a bit harsh. Razing a city already has associated costs.
If you are playing domination it won't matter as you will soon acquire more cities and one of them won't increase the tech cost (based on the max cities ever held), but if you are just dealing with an aggressive neighbour and want to raze one of his cities, you can end up with a permanent tech penalty. When I discovered this, I was kind of forced to take another city and keep it next time he declared war.
Thoughts?