RE: Aircore planes
Why? I have seen Aircores or similar British versions in Hong Kong that are not bad but not great either.
I would recommend a balsa trainer since you are already working with a balsa kit, repairs should be straight forward. If you get the right instruction, crashing shouldn't be a big issue.
I'd say go balsa... they are beautiful planes!
And, for my namesake, a 4 stroke engine in a Kadet is very retro cool. (Even though 4-strokes aren't retro at all :-)