Before you go all gun-ho on Tygon. It's not perfect. If you search the procooling forums you'll see there's alot more information on it. Much of it contradicts the original posting. The original poster made alot of suppositions based upon using it for about 2 hours.
Tygon is nice, but it's not really better the silicone. They're both very smooth interior walls and depending on what version of each, they have good turn radiuses. Tygon has higher-end stuff with very tight turn radiuses but that's about $10/ft at mcmaster and $8 at usplastics.