Its always a feeling to keep things stock. However, this is your FJ and if you want to do a conversion, you should do what you want since it is your vehicle. The only reason I am posting is I don't want you as a new person to our site take the above comments other than meant as a suggestion. If you have decided to do a conversion, then don't feel bashful about posting up
It comes down to what you want to do with your truck
I did a Disk conversion on my 73, a V8 swap, changed out the tank, Fuel Injection, 5 Speed tranny and more. I had folks telling me I should leave it stock, but it came down to what I wanted to do with it
Surely a stock refurbished FJ25 may be worth more for resale, but it comes down to your priorities