One thig I allways do
reinforce the firewall.
Really beef it up.
Fiber glass layers and L shaped balsa..
I will be putting a 110 YS. which is the same size of the 90, well it is the 90 bored out.
When I get the engine i will take some picks on how much I beef it up..
Adds some wait . But a few ounces is well Worth the extra beef up...