1) each hard drive has a different shock rating. if you check the specs on the box or website it should list it. most will take a suprisingly large amount of shock. if you want to be really safe, invest in a laptop hard drive. theyre smaller and more durable. personally im not concerned about it. if something goes wrong ill just try to rma the drive
2) Its up to you whether its worth it or not. theyre usually more expensive thatn a custom built system. youd have to give me a specific example of one to tell you if it has anything special
3) some pepople like to keep their decks some dont. you dont have to, you can run everything from the computer (this is my goal).