what kernal are you using for a stable 2 ghz? Also does anyone know which governor is the best I don't know the difference in them.
I'm running speed demon 5.0 right now. Most kernels would do 2Ghz for me but I bumped into a few, even different builds from the same developer, that would make my phone quirky at that frequency.
Basically over volting your cpu is always a risk. No matter what you always have silicon migration when you have electricity moving through a circuit. Raising the voltage increases the rate of degradation and raises the thermal output both of which will, no matter what, shorten the life span of the CPU. There's just no way of telling by how much.
I say if it runs stable and cool you're probably fine. You will be shortening the life span and if I were worried about keeping the same phone for 5+ years I would be concerned but I'm not.
Heat's what will kill it quickly. You also have to worry about applying too much voltage but if you're just using the stock voltage table and not over volting beyond whats default in the kernels that shouldn't be a problem.
It's very similar to overclocking a PC in most regards. Be reasonable with the voltage, keep the temps at a safe level, then just start increasing the frequency until it either becomes unstable or the temps get too high then back it down a little below that threshold for some wiggle room.
It's no worse to oc to 2Ghz than 1.6Ghz if you're using the same voltage. You just have to check you tables and use incredi control to set the voltage as low as you can while keeping it stable.
I also use the smartassV2 generally because it seems more responsive while giving me ok battery life. I tried savagedzen and interactivex for a while, but they felt too sluggish and ondemand works ok but it draws more battery.
[EDIT]
I forgot to mention that this is my second triumph because my first one started to develop a bad connection on the USB port. My first one would OC to 2Ghz fine also and it would actually let me undervolt more than my current triumph does. You just have to remember than not all CPU's are created equal and it's mostly a matter of luck what your max stable OC is.