I have a 2001 GT Convertable with the Mach 460 sound system and am looking to swap the head unit out and leave the stock speakers. I'm currently looking at putting in a Kenwood KDC-MPV5025 head unit. If I get a wiring harness, will I have any trouble with using the Kenwood with the stock speakers? Also, where can I buy one of the compartments to place under the new head unit to fill the space? Thanks in advance for your help.