The 2000 S I recently acquired had 4 fairly new tires - less than 6 months old, but the steering wheel shook and balancing didn't fix it. The left front was cupped moderately on the inside so I decided to replace both fronts, which were directional tires in the Formula 1 rain tire tread pattern. My experience is that those style tires develop uneven wear pretty quickly and they get loud pretty quickly too. So I looked at all 225/40/18 tires at Tire Rack trying to find some asymmetric tires rather than directional tires. At least I would be able to rotate them from side to side to even out the wear and try to keep them from getting nasty loud. This is the tire I picked, a Kuhmo.
The tires are nice and quiet but I've lost some of the steering responsiveness, which is a pretty big deal since the Boxster is about chassis communication. Now the car understeers more than I like. It's almost like I need to get some squirmy tires for the rear to match the front, lol.
What kind of tire pressure adjustments reduce understeer? I'm running 29/36 right now.