Get WD Red instead. The number of issues I've had with Seagate drives is just astounding. It's $20 more, but it's worth it.
In terms of GPU, I'd wait and see as RTX 20x series will have an impact on GPU prices. I wouldn't be surprised if soon you could get GTX 1080 in $300-$400 price range. Also the rumor has it that AMD might refresh its Polaris series in Q4 2018.