Pipen, if you may be contemplating swapping a later motor, I wouldn't. The 2F is a great offroad motor, and a wise choice for Toyota to install. Granted it's far from economical, and slow, it makes up for it in just sheer grunt, and with the right gearing can make a cruiser climb a tree. If you were interested in better performance, you can look into dropping in a later carb and intake manifold, but the overall gains wouldn't be huge.
Also, there are some who will tell you to put an aftermarket carb or headers on this, I say keep it stock. The reason is that toyota designed this engine to get the best overall performance, and balance fuel intake with overall torque, a Webber may give you more torque, but your fuel consumption may suffer, likewise, people say that headers will improve performance, but, honestly not too terribly. What will improve is the quantity of headaches you invite in trying to wrench down problematic mods.
For the soft top, SouthbostonFJ is a great guy, I bought my rocker panels from him, and Ehsan makes a very good, very workable product, I'm sure they'll be able to help you get a nice top (which would look great on your green beastie, there).