They are a lot of money for such little gains. I've even had guys tell me that they have made the sled run worse. IF they were more reasonably priced (say $120) I might buy them and try them.
In 300-400 miles when your sled will not idle and runs like crap you will be wanting to check them. They will be chipped or even broke right off. Hope you kept your stockers!
Well, I ran a set in my 800 dragon and could definitely tell the difference, although I did break a reed one time, but I think it is from overheating the engine, not sure though.