I used the "gentlemens touch", which is the razor method with a slight twist. I don't pry the IHS off I just stick with the thin razor and cut around, it only takes a few mins longer and minimises the possibility of damage. For sake of experiments I decided to increase vcore to 1.2v on my delidded 3570k and shoot for 4.7GHz again, all seems to be well right now, but temps are about 10c higher.

4.5GHz > 1.12v > max core temp 67c with the CPU fully loaded running BOINC
4.7GHz > 1.22v > max core temp about 78c with the CPU fully loaded running BOINC

The question for me (and this will apply to you as well) is do you run the extra voltage for +200MHz? The only real reason for doing so would be for epeen as real world applications you aren't going to see the benefit of that +200MHz. If you are really hellbent on max speed then as I will likely do investing in the services of a NZXT Kraken X40 would be a wise move, although for a cooler it is pretty expensive really.