These are the best you can give your Twins! The V1's are the crown jewel for Hpi Twin owners! They have our four outlet stinger design that only Jetpro pipes have and make a menacing sound that will scare away most animals! The power they deliver is off the map and your tires will hate you! These pipes can only be found here because they are sooo hard to make but ask the people who own them and they will tell you they are well worth there weight in gold!