GTA IV REGION LOCK

http://cdr.thebronasium.com/

Нет, играл в ГТА 4 на терр. РФ и Украины.

Nope

CTR+C, CTRL+V:

Open YOUR Steam store page, hover on "Add to cart" - check what URL it have, example:
javascript:addToCart(2011707);
Then go to Russian Steam by adding ?cc=ru to the address. Hover on button again - if game ID is same, then there is no region lock. MOST (90%+) games don't have any locks.