this has been asked numerous times so first off do a search, basically you have two options, you can either buy the east bear kit which is a r34 gtr style kit that fits to a gt-t, this can be purchased through powerplayimports.com, secondly you can go about sourcing a r34gtr front bar and guards (the gtr guards are wider) and then either purchase a gtr bonnet (involves replacing the hinges latches etc) chop the gtt bonnet or buy the east bear bonnet, either way its not a cheap process though
good luck