The TL/TT-01 are basic, plastic tub chassis kits/RTRs aimed for beginners and good for bashing and low level racing. The TA/TRF series such as the TA-02/03/04/05 and the TRF414/415 are belt drive cars aimed for enthusiasts and competitive racing. The TA-04 is essentially a plastic tub chassis version of the TRF-414, otherwise they share the same suspension parts. The TB/EVO series are shaft driven models for the higher-end racers, counterparts of their belt driven cousins. The TB-01 is the plastic tub chassis version of the TB EVO II, while the TB-02 is the plastic tub chassis version of the TB EVO III. There are currently no direct plastic tub versions of Tamiya's flagship cars, the TB EVO IV and TRF415.
HPI Savage Flux HP | Tamiya TB-03