I put one of these together for a clubmate a while back. I pinned the firewall with toothpicks and epoxy. No other modifications were necessary - this is a very solid ARF.

It held up OK but he finally broke the firewall loose after one nose-low landing too many.

I peeled back the covering, reattached the firewall and reinforced the entire nose structure with panty-hose and thin laminating epoxy. Don't laugh untill you've tried it - this works great!

That repair held up wonderfully until he got disoriented and crashed it short of the field. Broke off the nose (as a solid unit) just before the front of the wing saddle, busted up the wing.

He's retired it.