there is no difference, cuz there is not such thing as a "TRD tC" (figurativly speaking)
i know youre talking about the RS 5.0 TRD tC, it just has lowering springs, rear sway bar, and a exhaust, with different seats, different floor mats, a TRD badge outside and inside, and 18 in wheels. little things like that dont make it a "TRD tC"
in my opinion having a TRD tC is having all of the TRD parts: supercharger, short shifter, clutch, exhaust, LSD, springs/coilovers, struts/shocks, engine cover, rear sway bar, front strut tie bar, big brake kit, and a TRD badge (btw TRD badge=20 more horsepower << sarcasm). all of those make it TRD to me. then theres further "custom" parts you can get. but like i said, some are not worth it. 500 bucks for a muffler that has a louder sound?? lame.
is the RS 5.0 TRD tC worth the money? ehh, so-so if you wanted a limited colored car with different rims. but all that stuff can be bought optional.
just my opinion realy.
05 Scion tC owner.