If you are capable... KEY WORDS!!!
You can build a very good 3L for about $1200.
...oh yeah...
You can not call it a turbocharger...
Electric supercharger would be correct and for 2k plus for very limited use, only WOT, and an IMMENSE task on the electrical system it's definitely NOT worth it.
They are running 3 gear reduction starter drives. That's 300-400 amps of sustained current draw!!! You'd need to add a couple deep cycle batteries to operate it properly.
I wonder how it effects the PCM and ignition system to spike everything like that???
Also your voltage would drop as well. For instance a single 100amp starter drops a 500cca battery to 10.5 volts under load.
How long would the alternator take a load 2 to 3 times it's max limit?
BTW - 405cfm would produce about 220FWHP on a "boosted" 2.5L engine.
300cfm NA = 165FWHP (stock SVT)
500cfm boosted = 275FWHP (SF turbo)