Its the bonnet catch assembly. So the lock and the and the (please excuse me, i dont know the correct name for it) but its what th lock ttatches too as wel. Have a look, you'll know what I mean by "L" shaped reo. Its the the thing the horns and lock attatch too.
Yes. Hinges are the same.
GTR bonnets usually for for arround $400 but shop around and you can find cheaper.
The bonnet lock and reo are around $75.. again.. shop arround.
They are very light bonnets. I think I weighed both GTST and GTR and off the top of my head its about 10kg and a heap less understeer