I have 5 k sia is the enough to share my hdd?
The minimal collateral required to set up a host is 2000 Sia, so you'll have enough for experimenting with hosting. However, you will need much more if you plan to host more than a few GB. But just remember all that collateral will be returned to you if you keep a good uptime (97% or more) and you keep the renter's files during all the contract (3 months by default).
After fork, when ASIC come into circulation, the price of SC will skyrocket? do you think, or will reverse the principle, because there will be a lot of coins?
No, there will be the same amount of coins generated per day after ASICs are released. In PoW coins the difficulty adjusts with the hashrate on the network, so the block time, and the reward of mined coins, remains stable. The hardfork of tomorrow precisely introduces a new algorithm for the difficulty adjustment that can cope with dramatic changes in hashrate and still keep the block time in 10 minutes.
In general all the coins that introduced ASICs in the past experimented an increase in the coin value. But of course that can't assure Sia will see the same phenomenon. BTW, ASICs will not be delivered until April-June of next year.
Wait a fork is incoming for SIA blockchain too? Please someone explain to me what kind of fork we are speaking about and what the consequences for holders of SIA will be? Do I have to do anything? I still got my SIA on Bittrex but want to transfer them to a paper wallet soon, is this advisable to do before the fork? Thanks in advance.
No consequences for Sia users. If you are using the client, just be sure you are using the version 1.3.0. Bittrex is already prepared, so they will keep working normally after the fork. For more info check:
https://blog.sia.tech/reminder-upcoming-sia-hardfork-e0ffcde9ebcc