Sway Bar End Links

I had to replace the Sway Bar End Links on my 2006 Impala SS after about 30,000 miles.  When I did, I opted to replace the OEM links (which had rubber bushings) with Moog® links
Front Sway Bar End Link(which have polyurethane bushings).  As a result of moving to polyurethane bushings, the sway bar end links have less compliance -- the bushings deform less when forces act upon them.  

Comparison between the OEM links and the Moog links
The result is similar to replacing any other rubber bushings -- the ride is slightly firmer, you feel more bumps and jolts, and the ride is generally harsher.  At the same time, the car feels slightly more responsive, especially when you're doing something that otherwise affects the roll-balance of the vehicle, such has turning the steering wheel.  This is to say, the car's turns are a little crisper.  

Individually, just changing the links (and, more specifically, the bushings) won't make that big a deal.  However, each change you make improves the handling performance a little bit -- all of the changes add up.

The other downside to swapping from rubber bushings to polyurethane bushings is that the bushings need to be lubricated more frequently or else they start to "complain."
Rear sway bar end links

I've posted a few pictures of the new Moog Sway Bar End Links on my Impala SS here.  You'll notice that the fronts are basically a carriage bolt with bushings, spacers, and washers while the rears are basically a long rod with bolts in bushings sticking out in both directions (perpendicular to the rod).  You'll also notice that the front links haven't been tightened in this picture yet.  You'll want to torque them to the manufacturer's recommendation.  You'll also want to replace both links on the same axle (both fronts, both rears, or all four) at the same time.

I'm very pleased with the repair / upgrade to the new Moog sway bar end links.  The project took a few hours, mostly because I didn't recall that torque, expressed in foot-pounds, can be multiplied by adding more feet (using a longer ratchet / breaker bar) to get the seized hardware loose.  Both the fronts and the rears had quite a bit of rust on them; in fact, one of the fronts sheared in two before the nut would come loose.

Note that these links are for 1 Moog Front Sway Bar End Link kit; you'll need to purchase 2 for your car

Note that this is for 1 Moog Rear Sway Bar End Link kit; you'll need to purchase 2 for your car