Cut the weight and the Aircore 40 is a very good plane. You lose a LOT of weight by using CA instead of contact cement. (sand the place the glue will bond and it sticks VERY well.)
Delete the decorative pieces. (not a lot of these... mainly the windows)
for more tips on building using CoroPlast (which is the Aircore's material) visit
www.spadtothebone.com.
BTW... I'm building a coro trainer (my design) with 48 inch span which should do VERY well with a .15 to .25. (competitive for COMBAT with the .25, and deleting the landing gear, if I'm right...) Test flight by Sat.