I have a Firestorm 29D (3 * 12 gears) bike. The shifting is not smooth at all. I would like to upgrade my rear derailer and shifters or groupset to Shimano altus or any other. Kindly suggest me if its possible to do so. Current configuration: Shifters: Microshift TS38-8 3X8 Speed Crankset: Prowheel 24X34X42T, 170mm BB Set: Sealed Cartridge Freewheel: Steel, 12-32T 8 Speed Wheels: Alloy Double Wall 36H Rims Rear Derailleur: Microshift RD-M25