I'm not 100% as I am still learning about exhaust systems and such. But the GT has a VVTi engine while the GTS has a VVTLi so they would each need a different one in order to make the part fit. Also the GT TRD exhaust can squeeze more horsepower out of the GT than the GTS since the VVTLi is already such an efficient engine whereas the VVTi is less efficient