Want a cheaper alternative?
Try getting some new brake PADS first. Most stock brake pads are ROCK HARD and do little to slow you down. Get some new brake pads and you'll notice an immediate difference. Don't buy Shimano replacement pads, they're no better. Get some kool stop or WTB replacement pads.
Similar to these:
WTB
or these
Kool Stop
L8R
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger