[sperry]

Not to be rude, but unless you have a specific swaybar question along the lines of "I running a 22mm front, 24mm rear swaybar setup and I'm still seeing understeer on corner entry", chances are your questions about swaybars have already been answered in other threads. Try searching here, on NASIOC, and on I-club... you'll probably find thousands of threads, including the specific application of Perrin bars on wagons.

Now, to address your question, on an otherwise stock suspension, a stiffer rear bar will help to reduce understeer. Wagons already have a softer rear bar than sedans, so just picking up a sedan rear bar will help. I've probably got one just lying around my garage if you're interested... make me an offer.

However, an adjustable aftermarket bar would probably suit you better since you can soften it up in the winter when you want to avoid oversteer.

As far as end-links... links don't make a bar any stiffer, however, they reduce the lag time between the car's weight shifting and the swaybar taking effect. So links will make a rear bar seem more "crisp".

One final thing about going to a stiffer swaybar, you should also upgrade your mounts as well. Having a bar tear out a mount is no fun.