Having recently suffered another flat tyre on my PX i decided to jazz the beast up with some conti whitewalls, i can confirm that:
1. They look good on a PX but do not stay sparkly white for long.
2. They are a nightmare if it rains, it's like scooting on ice or ice scooting as i now call it (generally, i'm shouting it whilst clinging on for dear life whenever i see a manhole cover).
3. They are not cheap, £40 ish each plus fitting.
4. Alarmingly they have the following printed on the tyre rim 'maximum speed 62mph' (even on a PX that is a bit of a worry).
On balance i would not recommend them.......look good but skid like hell
