Is it worth putting on a back of a cossie?

Just wondering if it makes the car handle better! wont be so much for launching as i got a std diff at the mo But for coming out of corners etc and putting power down to stop the back end trying to over take you

 

Cossies understeer round corners when your really giving it loads unless you on the power, thatl just make it worse.

Obviously itl help grip when you got your foot down tho