I know many of people who have lost Byron models due to hinges wearing out the foam. I would highly suggest replacing your aluminum tube idea and replacing a section of the foam with a balsa block that is drilled for the hinges.

The plastic steering arms could also prove problematic. I'd suggest replacing it with a piece of thick (.090" brass) that is silver soldered to the steel rod. Done properly this is a strong, slop free linkage setup. I believe your current setup will develop allot of slop over time (or break) if speeds average to high.