opinions of the gt 740 superclocked?

I think you are better off saving for a 750Ti much more suitable for gaming though a 740 can play on around low for good framerates and the 750Ti is more of a medium for the latest games.

Edit: As said below resolution matters a lot. 720p the 740 is perfectly fine but for 1080 the 750Ti is better.
 
I would buy no GPU lower than a gtx 750ti to play said games.

@OP: Beyond your target resolution (which matters a great deal in determining what kind of performance you will get), what are your full system specs that you will be installing this GPU on?

FC4 and BF4 are pretty demanding games!

Did you read Toms FC4 performance review article?

http://www.tomshardware.com/reviews/far-cry-4-benchmark-performance-review,4019.html

 
Yeah I would save up another $40 or the $80 will be somewhat squandered on crappy hardware imo. Ive seen plenty of used 7870s for example for $100 or less. One jsut sold recently in the Toms deals section. If your budget is truly $80 and you can't nickel up then id go for a used GPU. You could probably find a gtx 560ti or something similar for 80 or less.