I’m using a MPB 15 Mid 2013 (the first retina MacBook). It has a Core i7 CPU (”Ivy Bridge“) with a maximum specified temperature of 105 °C. When using it, it’s mostly running at temperature levels of 90 to 100 degrees. There never was any hardware issue and it still performs perfectly. In other words, this is normal.
A late 2011 MacBook Pro also has a Core i7 (”Sandy Bridge“) CPU. It’s maximum allowable temperature is 100 °C which means that 80 degrees is more than acceptable. From the processor’s point of view this would almost be ”cool“...
Apple has gone to great lengths implementing proper power and cooling management. I’d therefore strongly recommend you refrained from using any of those third-party tools which fiddle around with temperature management. I spent 15 years of educating prospective Apple Service Technicians the proper techniques of servicing Mac desktops and portables. And I cannot remember a single incident of a Mac dying from overtemperature.
The only temperature level you should really be aware of is that of your hard disk (provided you don’t have a SSD built in). This is probably the only component in your Mac which would seriously suffer from extended periods of high temperature. But this topic has enough potential for a separate AskDifferent question.