The Hanger 9 Edge 540 is a great flying plane, yes it can use some minor modifications. I added some reinforcement to the firewall and the horizontal stab sadle on mine but these were very minor mods. If you are going to bolt on that Saito 180, these modifications will keep your Edge flying safer and longer.
I was flying an ultra stick before buying the Edge and had no problems making the transition to the more aerobatic aircraft. The edge has no bad habits that I have found and sloes down nicely for landing.