Horse - the Wilwood's have NO dust seals. They are not DOT complaint for street use either. No dust seals means that you'll have to rebuild the caliper quite often to maintain it as well as prevent it from being damaged. The Wilwood's don't have anti-rattle clips either, thus will be considerably noiser then other calipers.
If you're going tracking alot and don't mind rebuilding the calipers, then they would be fine.
You have to remember it's ~$35-$55/time you rebuild the Wilwoods. To keep it in top condition for road use, that's rebuilding it every 3 mths.