The differences are just the brand name basically, plus the C's one is brand new, never been used and the No-name one has been used.
The best prices I can do would be $275 for the C's one and $200 is the best I can do for the no-name one. Both come with spacers and bolts etc.
Yes, the fit the AE92 twincam box. Not sure what gearbox that is. Whichever box came with the Jap AE92 twincam. Same as aussie GTi or SX rolla.
Selling these cos I got my hands on them through a friend and thought that someone may want them.