I can't answer your question about issues, but there are a number of questions. The engine seller mentions "most of the side wiring"... what does that mean? Does it or doesn't it come with a complete EJ20G engine harness? Does it come with the ECU (assume it does, but it's not clear). The link to the '95 Impreza shows the add has been removed - is it a manual or automatic trans? IMHO I'd do a lot more research before jumping into this project.