If they were for GTR, still possible to install on GTT. The only thing differencs is the length of your cat (or decat) pipe joining to the downpipe flange. Can ask any exhaust shop to fabricate it cheaply.
yesterday i just install my ground cable....
first is that my car is old..
so originally.. if open lights.. the rpm will drop a bit..
but then.. after i install ground cable, also same.. :(
dono...