The DF-03RA is a 4WD buggy chassis with shorter arms to fit under a Rally Car type body as with the Celica Body you speak of. The TT-01 is based on a touring car platform. I believe that the TT-01 has a little less ground clearance but is still capable of being a Rally Off road type car with the proper wheel and tire combo, just look up on youtube for RC Rally, and you'll see that the guys in Europe have made them pretty capable. With either chassis your not going to be taking on a 1/8th scale track but that's not the intended purpose of these cars.
Serpent Cobra S811, Which ever engine is running good for me, VP Fuel, Savox Servos
"A bad race day is still better than a Good work day!"