Absolutely none. There will be no detectable difference in PS4 sales (I'm talking like less than. 5%) upon PSVR's launch.
Edit: I should elaborate before I get quoted. The weekly sales will be higher because PS4 will increase YoY but the percentage comparing the average YoY to that week's will be nonexistent.
You should check out my YouTube channel, The Golden Bolt! I review all types of video games, both classic and modern, and I also give short flyover reviews of the free games each month on PlayStation Plus to tell you if they're worth downloading. After all, the games may be free, but your time is valuable!







