I had an accident on my mtn bike and mangled my Shimano STX-RC rear derailleur( no big loss, it's Shimano)....But my question is can I use an old NOS Suntour XC Pro Rear derailleur with the current equipment on my bike? I currently have a Shimano SL-m740 XT shifter, a Shimano STX-RC rear Derailleur (wasted), and a SRAM 8-speed gear set, the gears and shifter were bought new in 02...If i can't use the Suntour will a new Shimano XTR rapidrise work??