Thanks Fly, I didn't have to reinforce the inside the kit is strong enough, I did paint the inside black as I decided it would look better without the blanking plate they provide, I had thought about the idea of getting resin intakes which are all one piece but to be honest I think it would be a waste of time as I doubt on a 1/48 kit anyone would be able to see all the way down to the engine faces. For the APU I screwed a scalpel through the dent Revell have and sanded it smooth and rolled up a small piece of plastic card which I glued from the inside to create an exhaust, it's a simple solution which looks convincing.