The powerband for the .64 and s3 cams are both mid range. The powerband for the .86 and s4 cams are for more top end. Your setup will work, but it's not optimal. I had the HKS GT-RS (basically the .64) on an s14 sr (w/nvcs) and ran HKS 256/264 cams (more mid range). Here's a dyno chart documenting my "experience:"
