Need some Transmission advice
 

The transmission in my 84 300zx AE was destroyed when I got it. 1st gear will throw its self out immediately when you move the car forward, the linkage from 3rd and 4th gear is gone and the synchro's are so badly off that I had to double clutch just to shift easily. I've been on the hunt for a new transmission to swap it out with but I'm not having much luck and I was wondering if it'd be better to just rebuild it. Any ideas or suggestions anyone? I would greatly appreciate any help.

Most likely cheaper buying a used transmission. Head to a transmission shop and see how much they quote you. I have a 84 tranny with roughly 66k miles on it. Send me a PM if you like to buy it from me.

The T5 rebuild kits are cheap. Generally cheaper than a used transmission. If you can do it yourself, then it's money better spent.