We just purchased a 2014 Land Cruiser and I am quite disappointed in the sound, particularly the subwoofer. Has anyone replaced the stock JBL sub amp and/or stock JBL subwoofer? I'd like to replace one or both and keep the sub in the factory location so that we don't lose any cargo room. Was hoping someone had a reference for an aftermarket sub with sufficient dimensions such that it will fit the factory location. Thanks!