I control a Nin, the Pain Artist (without summoning sickness) equipped with a Basilisk Collar (or anything else which gives her lifelink) and a Soul-Scar Mage.
When I activate Nin's ability and deal e.g. 3 damage to an opponents creature, will I gain life, or will the Soul-Scar Mage with his replacement effect "put that many -1/-1 counters on that creature instead" prevent me from gaining life.
Also, will the replacement effect prevent the opponent from drawing cards? (I suspect not, since the card draw isn't tied to the damage)