Tim hit the nail right on the head.
The only thing I would add is that there seems to be some confusion about the different FMS boxes offered.
There are VERY old school blue boxes that don't have a screen at all.
Then, there are the FMS boxes that we traditionally see with a blue face. This is what Tim and I run. I can't really add anything to what he said above.. They are THAT good, even all these years later.
Finally, there is the Redbox. These are the 4k fueling boxes. They are not really street friendly, and I have heard from a few people that you lose certain gauges. There are sevearl peple that run them on daily drivers, so it can be done. Just depends on what you want to live with.
My FMS box lives on 2 settings, Off and Kill. If you only use it once in a while, the redbox might be fine. Otherwise, I'd pick up a blue box (FMS) the next time you see one for sale.