Sway bars will show a definate improvement in handling on almost any car. The guideline is the thicker the better, but there's a trade off. I noticed a difference swapping out my rear sway bar with a 24mm Aussie bar a few weeks ago. The trade off for me is the stock brackets are too weak to support a bar so heavy duty, so I had upgraded brackets put on.
The bars aren't hard to install. I did mine by myself and it took me about 2hours. I've never done one before, just took my time and read over a how-to a few times before attempting.
What model of car do you have? I have a 19mm stock svt bar I'm looking to sell for cheap.
Tim
'00 SVT