It should just mount up. My sound bar had 5-1/4's in it and I just put Alpine 6-1/2's in it. No cutting.... Just mounted right up.
10' JKU Mango Tango, TF perf. leveling kit, Rubicon shocks, 315/70/17 GY DT's, V-Tec Raptor wheels 17x9, fender trim, Warn M8000, SB front bumper, aftermarket HU and powered JBL sub., Cibie' H4 light upgrade, KC Apollo Pro's, etc, etc.