My car just threw a front right ABS sensor code and I was wondering which of these two parts I need to buy to replace it? Both say they fit my LS. :/

Cap or insert?

 

Insert. But first check wiring there. These sensors are quite bulletproof, but the connector and wire aren't.
Oh, and I forbid you to buy that chinesium ebay crap. Get an OEM, please!

 

I just took her in and spent around 3K on new tires, struts and, control arms, so I just can't afford an OEM right now. ):

I'm not trying to doubt you because I barely know what I'm looking for but I definitely have that cap.

 

Go for it. Anyways, you didn't specify your vin and drivetrain type, so I just ballparked 2008, awd (ok, it was my assumption) and saw that insert is implemented.