For those that are interested, the Group-N part numbers for the suspension links are:
Front/Rear Outer: ST2022044020 or B0220FE020 (Qty: 4)
Front Inner: ST2022044030 or B0220FE030 (Qty: 2)
Rear Inner: ST2022044040 or B0220FE040 (Qty: 2)
Rear: ST2022044010 or B0220FE010 (Qty: 2)
Front: ST2022044000 or B0220FE000 (Qty: 2)
The total price for these is between $175 and $225. Relatively cheap considering the huge boost in rear end stiffness and responsiveness.
Here's a diagram. I've circled the ones listed above. This should tighten up the rear end considerably.
A lot of people have asked me why I chose the rubber Group-N units over Whiteline or PolyPro. The answer would be personal preference. The Group-N's are rubber which should hold up longer without needing to be greased or re-packed. Polyurethane is stiffer, but often needs to be cleaned and repacked with grease from time to time to prevent squeaking and wear. There is a debate on whether or not to use polyurethane in rotational applications as well with good points being made on both sides. Basically I like rubber because of it's set-it-and-forget-it nature and it doesn't transmit quite as much vibration/harshness. Currently, my swaybar bushings, which are polyurethane, squeak/groan like crazy about every 10K miles. This is eliminated with a re-greasing.
Either option is WAY better than the stock bubble gum units.