You are not logged in. Grand Prix Net » Forums » Older Models » 1997-2003 Grand Prix » Stereo Question Register User Forum List Calendar Active Topics FAQ Page 2 of 2. It has a factory Monsoon stereo system (comes with the GT package), so I’m not looking to get a bigger amp or anything. I just want to replace the rear speakers since one of them cracked. I was happy with my system as it was. They’re 4x6 speakers, no idea what the wattage is. No idea what the specs are on the factory Monsoon amp.