VCore: In the Anandtech review of the S2E he says 1.5 is the max recommended. Under load the vcore is about 1.42 max, sometimes dropping to 1.4. At 450FSB I can only get stable at 1.45, at 1.4275 I can get stable at 445FSB - both with a 9X multiplier. At 4GHz I think 61C max is an OK temperature (this is the max at temp at 1.45V as well). I was getting the same temps on my QX9650 at the same speed, and that is a much cooler chip.
Yeah but I remember reading around here about people warning going no higher than 1.40vcore. Anyways, 1.50v for a 45nm IMO is beyond the line but since you have water, you might be ok? Not sure...

VTT: (I have this at Auto not 1.30) I think 1.36 is the recommended max, but on a GTL_REF of -51mV at 0.63 of reference voltage, 1.28 is the most accurate value you can set. On Auto this is the value I get anyway!
Remember 5010? He needs 1.20 I believe for his OC on the eVGA. 1.30 is not too high but for 45nm, you have to remember the cpu is more sensitive and some people even mentioned of 45nm dead because of high VTT so you might want to see if you can lower this and keep your OC.

Memory: 1.90V is the rated voltage for this memory at 1600MHz, so only a mild overclock. Some DDR3 memory is rated at 2.00V anyway using the same chips. I do have an open case as well so heat is not a big issue.
Is not that is in the danger zone but 2.00v is somewhat high considering the striker gives out more than what is selected.

SPP: You may be right on this, I have not tried dropping it as my temp is below 60C under load anyway. Again Anandtech says 1.60 max for the NB and SB. I will try and lower it and see what happens.
In my striker, the more I give, the more inestable lol. Again, not because they say thats below the risk, it is safe. 1.54 for me sounds like a little too much but thats just me. I also remember, some 45nms like high NB voltage to work at high speeds so you might just need to leave it there if you want to keep your OC.

Thanks for making me think again anyway!!
Just trying to help