What is the hardest C4 paper for Edexcel? I'm not planning to do the elmwood papers or solomon papers.. they'll rape me lol. I think the edexcel papers are good enough. Atm, i'm nearly done with watching all the video tuitorials on examsolutions for C4 for integration which really helps alot. Then i'm going to do some c4 papers open book. Could anyone please suggest which years, were the hardest for C4?