Specific
Hi
Can you be more specific about what you are trying to achieve?
Many people have added gussets on the lower weldment inside the cockpit, not easy on a completed aeroplane but doable, there are photos of this on my blog.
Also there is a mod on the actual engine mount welding in a gusset along the bottom cross member onto the gear leg mounts, sorry dont have photos of this but someone from the UK might, and if I can I will post them.
Both of these mods are designed to stop damage to the mount/gear/firewall.
Is this where you are trying to strengthen?