Heh, Walter and I will argue a lot about a Watts vs PHB. The Watts is technically better, but I not the biggest fan of the packaging of a lot of the Watts links, they tend to be a little bulky and I would like the see the arms be a bit longer. Replacing the PHB on our cars makes a huge difference in the feel of the rear suspension, so I wouldn't say a solid axle rear "needs" a Watts (though no doubt it makes a massive difference over stock).
Dan
Dan