I like osbot, has a laid back community, friends that you can confide things on, opportunities to learn how to script.
You can seldom find that on other botting sites.
Prevent chain bans, use proxies.
As for normal botting, highly suggested to use premium/private scripts, greatly decreases bans compared to free ones.
As for mirror, i don't think it helps much. As far as I know, breaks seem important to me.
If you were to upgrade the cpu, go for i5-6600 instead.
Recommend to get 2x4gb ram over a 1x8gb ram
Go with rx 480 instead. It outperforms r9 380 anyday.
The rest is fine.