What can y'all tell me about Shimano STX 7 speed Rapidfire shifter/brake levers, I am looking at buying. They have cantilever brake levers, and are said to be in great shape. I am going to use them to upgrade my Gary Fisher. Also the current shifters are suntour, and the r/dr and shifter seems to be indexed. I am guessing this since it clicks when shifted. The f/dr and shifter seem to be friction, no clicking. So does that mean that I have to change the f/dr but not the r/dr? Let me know if I have this right or not please.