RE: LAST one
I have a Porter like the one pictured above. This is the early, non-turbo version. I believe it was a Czeck ARF. No Dihedral, bolt on tail and rudder.
I am flying mine with a First Place Engines 1.3, and it flies very scale. Everything fits in the cowl. I imagine a Zenoah, G 26, Fuji 32 or G 38 would be great. I also know people have flown these with 50's for glider towing.
I believe the wingspan is 80". I used Hobby Lobby servo pockets, and reversed them, gluing them into the wing, to make a removable servo system. THe only thing touchy was cutting the windscreen.
I don't know anout the Jamara version. It looks good though.