8 psi SAFELY and EFFECTIVELY?????

You can boost reliably and safely on 8 psi. I have for a month. Now, I am boosting between 7 and 8 because I don't completely trust running my car at that boost without dyno tuning it. I need to get my butt into the shop and on a dyno. You can boost at 8 psi using the Greddy FCU (blue box) but dyno tune it when you crank it up to see where you are at.
If you have the cash to get engine management, $700 to $2000 for Hondata, then you can boost much more reliably at higher levels.
The Greddy FCU is "adequate" for boosting up to 8 psi and is even safer when you have 93 octane or above fuel, an intercooler, and if the weather is cool outside. That would benefit all FI'd cars too though.
The reason I like my Greddy FCU is because I want to go to Hondata soon and did not want to waste money on several other devices that Hondata would replace - VAFC, rising rate fuel regulator, etc. Anyway, hope this helps.
Steve