You should never disable C1E, cause this mode is very useful to reduce CPU TDP with no load/standby. By disabling C3 you will lost hibernation availability. More deep states are targeted to special mobile applications (phone/tablet-like sleep modes) and unlikely will be ever reached on desktop without special programming.
it is risky? better not to do it?
This will not lead to immediately troubles, but in harsh environment can decrease a CPU lifetime. Really dangerous is disabling of Intel Thermal Monitor (ATM) option, cause ATM is responsible to protect CPU in case of drastically overheating.
The features that you are referring are only active when your system is idle. They are not going to improve your system performance while you are working.