Electronic components don't like running hot. Sure you can fit heat sinks and coolers, but heat is the number one enemy.
You should never plan to run a PC hot for long periods. The components will degrade faster and one common result of degraded components are BSODs. Its not the heat per se, its the rapid degradation that the heat causes that results in BSODs.
Short term high temperatures are much less of an issue, though over long periods of use even short periods of high temperature will degrade components.
A basic rule of PC design, especially if you build it yourself, is to run it as cool as you can.