If you plan to use up to 8 PS Eyes then this equpment looks a bit overkill.
Single SSD drive (even not dedicated) is quite enough for recording with 8 PS Eyes, no need for a RAID unless you have other tasks for it. And it won't offload more work from CPU during recording if you meant that.
Yes, these multi-controller USB 3.0 cards from StarTech show good performance with PS Eyes and are quite useful. However, you should be able to connect at least 4 PS Eyes to onboard USB controller(s) in case there are sufficient number of available USB ports. For another 4 PS Eyes you can get one dual-controller card with 4 ports (2 ports per controller)
https://www.newegg.com/Product/Product.aspx?Item=N82E16812400547&cm_re=PEXUSB3S42V-_-12-400-547-_-ProductEDIT:
Also, be aware that Basic license supports up to 6 PS Eyes, and for 8 PS Eyes you need Pro license which is substantially more expensive. You may start with 6 PS Eyes and 3-month Basic license to get acquainted with the software. And if you see that 6 cameras are not sufficient for motions you track or you need some advanced features of Pro edition then purchase Pro license for the next period.