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, SuperChips Flashcal, Diehard Platinum battery, etc.
98' TJ...gone but not forgotten.