the "newer or better" gearboxes come in all tamiya tigers now. They are the ones with the black plastic covers. 1st generation gearboxes didnt have those covers and had a different gear arrangement. Those boxes would torque and self destruct over time. If you do get the metal tracks for the kit it is HIGHLY ADVISEABLE that you put a rubber bush around the rear idler/tensioner axel or there is a 95-99% chance it WILL shear one of the axels from the tension and added weight of the metal tracks. The suspension overall is very good and very rugged. personally i dont believe it needs any kind of enhancement. Personally the added expense of the "UPGRADES" for the recoil and suspension arent really that important and what they do add to the model is barely noticeable at best. IF What you pay for those upgrades and what you get in the end is worth it is up to you.