I just bought a 08 Chrysler Town and Country minivan and now want to replace the speakers in it but I don't want to replace the factory nav deck. It's got 6x9's in the doors and rear panels, 5-1/4's in the dash and center, and a 8" sub in the back with the factory amp. Would replacing just the speakers make any differance at all? It's got a factory VES system with sat tv that works with the factory nav deck and I would really like to keep everything working. What do you guys think? What are my options?