AMD chips have an official max of 61c, which is why it throttles at that temperature.
Here is a link to that effect:
http://tinyurl.com/93dvz3c
Lowering the vCore - Changing the vCore can cause stability issues, yes. That is part of why I would advise reading up on it before you do it.
Lowering the vCore essentially tells the motherboard to feed less power to the CPU. If the CPU can operate just fine with a lower power than its currently using, then there is no problem.
If the CPU is already on the verge of failing to get the power it needs, then a reduction would put it beyond the break point and cause all sorts of stability problems.
The important thing is the gap between the min and the max for stability. The closer you are to the minimum when you are in that gap, the less heat your CPU will generate.
If you don't feel comfortable messing with such things, that's fine. 99% of people don't mess with such things because there is danger involved and potentially zero upside.
There is also potentially a lot more than zero upside, but you are guaranteed nothing. Each component is ever so slightly different from others of the exact same model so even the exact same hardware can have different results.
There are plenty of other possibilities as for things you can do. You could just accept being throttled dynamically, or you could try a different cooling setup, or stick with the temperature targeting and possibly throttle yourself all the time, etc.
The point is just for you to get into some kind of area you are comfortable with.