Hi, I Have audi TT TQ 225 cabrio, with Bose Sound system & Audi NAVI & Audi Car kit, also i have Concert I (Radio Casette Tape) and audi 6disk changer i Have replace front and read speakers with better. can i replace bose amplifier with other??? someone have wiring of bose amplifier???? PS. I dont whant loose NAVI & car Kit.