You need to consider a few things:
1. You'll get much less, if any, boost with this on a larger motor (V6 or V8), because the electric supercharger just can't keep up with the CFM demanded by a larger motor. This same guy did a video on a mustang where they actually lost power.
1a. The torque amp website even has a video that even mentions this, but then points out that their product did increase torque, but at a much lower RPM. What he didn't say is that this means you're losing a lot of horsepower in the upper range of the rev band.
2. Even on smaller motors, you may need to change the injectors to provide enough fuel to maintain the proper AF ratio. Most traditional super or turbo charger kits include new, higher flow injectors for this reason.
Just because they made more power for a few seconds on the Dyno doesn't mean the motor is going to be happy doing this on a regular basis, long term. If it's running too lean, that will melt things, like
plugs and valves.
3. You need to find a home for that big booster and 48v battery.
4. I'd be concerned with the extra loading on your battery and alternator. When you consider that the voltage is being boosted 4x, plus losses. Check out the wire gauge they're using. That's a lot of current. They say the booster is turned off when the electric motor is being used to provide boost, but then the 48v battery needs to be recharged. Ultimately those thousands of Watts have to come from your electrical system.
5. For $5k, there are probably better ways to make more power
6. Never trust a guy named Cleetus wearing a lab coat. Lol
I'm not saying electric supercharging isn't possible, in fact some manufacturers are beginning to use it in certain applications. I'm just saying it's not easy, and needs to be very carefully engineered, as a system, to be effective and reliable for day to day use.