The 337 was all wood so I cant comment on the glass. I can tell you that it was built like a tank though, and I was not worried about it falling apart! It was definitely more on the solid/overweight category than flimsy.
For a Cessna push pull it did some nice rolling circles, point rolls and even hovering. I am not allowed to do this anymore though because apparently we lost some axillary batteries during the aerobatics.
The prop jet may be completely different, but the 337 was solidly built. The fiberglass for the cowl was quite sturdy.