got this game last night and it is fucking AWESOME, i was looking at the content download and one of the expansion pack things, says you play as a sort of clone of lara croft who's evil and has magic powers or something?

could anyone who's downloaded this tell me what its like and if its worth the 800 points? magic powers seems kinda weird for a tomb raider game, wat sort of stuff do you do?
also, the free costumes you can download, when you download them will they replace the costumes that she would be wearing in the game with the ones i downloaded? or do i get to go into the options and decide whether i want the new costumes on or off?