So on Craigslist there's a guy selling for $300 a Gtx 970 strix and with modded bios at 1700mhz core an i5 4690k at 5ghz with 68c under load a msi gaming 5 mobo and 8gb of crucial ballistix. It's a really good deal by the looks of it but I'm worried about whether or not to go for it because of the extreme overclocking, or if I should get it as these are silicone lottery chips. Just asking for your opinion here. Thanks in advance for any replies!