Today I installed a sway bar removed from a Jeep Cherokee, on my P15. The Jeep sway bar had a much larger diameter (26 MM or 1.024") than the original P15 bar. Took a bit of fabrication to put it all together, but the old gal has much refined road manners now. Took a ride around the neighborhood, about 5 or 6 miles, and it seemed to work well. I think I'll take it out on the highway tomorrow and see how that goes! I'll try to post some pics if anyone is interested.
Wayne