Save your cash and get a piece of AR500 plate cut.
Or two or three. For home use you could easily preposition several and lie in wait behind them.
Without a chicken plate, its only rated to 9mm subgun.
Secondly, even a bullpup carbine or subgun is a challenge to use when dealing with the shield. Laser sighted handgun is still the best firearm for shield work.
Between multi agency trainings, and a number of other callouts, I ended up with one of the two shields in the county more than once.
A couple of old soft vests hanging from the car doors and off the back of the drivers seat are much easier to deal with and cheaper.