My latest little viper mod, and an oldie that is really worth making sure you do........
I found the canopy frame very flexible one the lower cross braces of fiberglass were removed. This made handling it when it was off the model tricky and after a few " Harder" flights ( Especially those with snap rolls ) I found the rear edge of the canopy frame starting to open out. I didnt deal with this quick enough and ended up with a tiny hair line crack in the very top of the frame where it had opened out more and more.
My fix was to put a cross brace in. What I used was a 3mm carbon push rod with a threaded adapter at both ends, with a clevis attached. This was I could adjust the length of the cross brace a little to get it just right. I then cynoed, and rocked powdered the very top domed part of two fiberglass servo arms into the corner of the frame as attachment points. Job done! The frame is allot stiffer now, nicer to handle when off the model and can not open up in flight.
The oldie to make sue you look out for is to make sure that you gently heat the flap faring attached to the flap surface which lips below the top surface of the wing, then while warm flew it gently so it rolls under more and clears the top skin of the wing. From the factory these tolerances are a little close and I have found in flight that with a little wing flex the flap can actually catch the wing as they raise. On more than one occasion I have had it where one flap has caught and not gone fully up. Causing the model to roll a small amount in flight, ruin that flight, stall the servo and damage the wing skin a little. A gentle warm with a heat gun ( Go easy as its thin glass in that area ) and a tweak down has it sorted.
Hope these mods are of some help