Looks like a good kit at a good price to me. Chain is top quality. Re the front and rear sprockets: the front sprocket having a rubber type damper on it in no way diminishes the structural integrity. Not seen a rear done like that, but IF it is the same construction as the front then it will have no effect on the operation of the rear sprocket at all, it just make the chain to sprocket contact more quiet. In other words I believe it is a solid sprocket like the front, but with a rubber damper 'glued on'.
