Not photoetch, but Engines and Things makes a set of engines for it. They go for about $12us. Their products are sometimes not super crisp, but they will likely be a lot better than what's in the kit.
You may be able to use a generic p.e. set or two from Tom's Modelworks for cockpit bits and such. Eduard has generic sets for stitching, lacing, seat belts, gauges, etc.