Sorry I didn't see this post until now; my account was deleted due to inactivity.
Regarding the 5th gears, I keep these in stock at all times including some other rare JDM parts for Evo 1/2/3's as I have a direct account with Mitsubishi of Japan. I also still have my main account with USA Mitsubishi, so anything in the USA I can get as well.
I order regularly from Mitsubishi of Japan and can get rare parts that are not available in the USA for the GVR4, Evo 1-10, and any other JDM Mitsubishi. Shipping is a bit slow as it comes via slow-boat, but the parts are normally in stock and I can get them.
I also am able to get 3000GT VR4 5-speed and 6-speed parts, JDM GVR4 parts, etc.
Here are a few JDM parts that I keep in stock currently:
Evo 3 2nd Gear Double Synchro
Evo 3 3rd Gear Double Synchro
Evo 3 4th Gear Double Synchro
Evo 3 1/2 Shift Fork (steel)
Evo 3 3/4 Shift Fork (steel)
Evo 3 3/4 Shift Rail (Forged rail end - interchangable with late 91-early 92 DSM and all GVR4 late 91-92)
Input Shaft (Evo 1)(requires Evo 1 1st/2nd gears, and Evo 1 reverse idler gear lever)
Input Shaft (Evo 3)(requires Evo 3 1st gear)
1st Gear (Evo 1) 2.571 Gear Ratio (20% taller than DSM 1st)
1st Gear (Evo 3) 2.750 Gear Ratio (12% taller than DSM 1st)
2nd Gear(Evo 1) 1.600 Gear Ratio (5% taller than DSM/GVR4 2nd)
Evo 1/2 3rd Gear (large diameter single synchro design) (4% shorter than DSM/GVR4 3rd)
Evo 3 3rd Gear (double synchro design) (4% shorter than DSM/GVR4 3rd)
3rd Gear Subgear (required for Evo 1/2/3 3rd gears)
Evo 3 3rd/4th Hub/Slider (accomodates double synchro 3rd/4th Evo 3 gears without machinework)
Evo 1/2 3rd/4th Hub and Slider (accomodates large diameter single synchros on Evo 1/2 gears)
Evo 1/2/3 3rd/4th Gear Hub Springs
Evo 1/2/3 3rd/4th Gear Hub Keys
Evo 1/2 4th Gear (large diameter single synchro design) (4% shorter than DSM/GVR4 4th)
Evo 3 4th Gear (double synchro design) (4% shorter than DSM/GVR4 4th)
Evo 3 10% taller 5th Gear
Evo 3 5th Intermediate Gear
Evo 3 Reverse Idler Gear
Evo 3 (2G) Reverse Idler Gear Rail
Evo 1 Reverse gear idler lever
Along with many, many more parts.
Let me know if I can help!