I approached my local bike shop(independent) about changing my rear sprocket and installing an o-ring chain on my 2009 TW 200. He quoted me $150 for labor, as I have the parts. Is this way too high? I have read threads on here where most do this themselves-is this not too hard for me to do? I am somewhat mechanically inclined and have a good number of good tools. I have the shop manuals downloaded, any tips would be much appreciated Please help!! Thanks!!