I have the JL Audio 10” Stealthbox as well with 500 watts from a JBL A5055 amp running it, it is really disappointing as far as output goes. Are you experiencing the same thing?
I have the Stealthbox, honestly for $1,200 its performance is seriously lacking, even with 300 watts going to it. To use the Stealthbox, you will need an amp and PAC module. You will also lose your center channel. The factory amp is attached to the stock 8” sub box and won’t power the JL sub.