In a recent update they delayed the deafening sound as to not muffle the explosion of the grenade itself. I think it was in the same update that had de_prodigy but you get check at steampowered.com if you want.
I'm still new to mapping so I can't answer your first question, however I do know how to make buyzones;
1. Creat a brush where you want your buy zone to be.
2. Change the texture to tools/toolstrigger.
3. On the right side, click the toEntity button.
4. Change the Class to...
Before hitting enter you need to click on the Clipping tool icon. It alternates between having the first secion red the other white, the second section white the other red, and the entire thing white. When you hit enter it erases the red part. So if you have clicked the icon untill everythings...
After getting shot or shooting others, open the console and it will say something along the lines of
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Damage Taken from Blah: 21 in 1 Hit.
Damage Given to Blah: 132 in 4 Hits.
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