You'll need a CPU heat-sink just in general with the 6600k, it doesn't come with one. PSU, anything highly rated and by a major brand is usually fine but theres a thread for PSUs. I would get a 400W one at least. For the OC itself I can get 4.4GHz at 1.3V but you might not be able to, it varies by CPU. 4.3GHz is definitely stable though.