So I crawl under my '91 US-323 (not SE) to measure the rear sway bar with my brand new, hi-tech $10US vernier caliper & guess what? The outside diam isn't 16 or 17mm as I expected from:
http://web2.airmail.net/emann/proteg...uspension.html
• “Sport” suspension uses a 20mm front swaybar and a 16mm swaybar on all US Protegés except MP3.
• “Hard” suspension uses slightly stiffer (by ~15%) springs & struts than “Normal” and a 17mm rear swaybar.
I measured 25/32" (19mm?)!

Does anyone know what's standard for the rear sway on the 323? I was ready to swap it out but 19mm sounds pretty 'sporty'.

 

For the 1990, the 323 rear swaybar was 20mm in diameter. They may have made a running change to reduce oversteer, as I've heard the '92 or later LXs have a 22mm rear bar (up from stock 20mm), so this kind of thing is not uncommon.