TA05 is newer so finding parts for it will be easier. I have both a TC4 and a Cyclone S, I dig them both, for different reasons. I'm not a drifter, I like grip. The TC4 feels snappier out of the corners, while the the Cyclone feels more planted all the way around. I think when it comes right down to it I think I'll most likely race the TC4 probably. The Cyclone is breeze to work on only 4 screws hold the diff in. I will say this with both my cars geared close to the same with equal motors in them I can break the back end loose with the TC4 even on rubber tires. If you decide to go the Cyclone route buy new C hubs before you even build the kit. The stock C hubs that come with the Cyclone are crap. I swear if you look at them wrong you can break one. The C hubs for the HPI pro 4 are a direct replacement.