Thought I'd try both on my 115 E-Tec. The Rebel is a 15 3/4 X 15, the Viper is a 14 3/4 X 17. I like them both; the Rebel for slow to midrange handling/holeshot, the Viper for top end.
But as I was putting them up today I noticed a significant difference. The Viper has a smooth regular finish, the Rebel looks like a cheap knock-off with it's irregular surface. Are all the Rebel's this way?