monsoon
The monsoon is an adaquate stereo system. Meaning it is better than the average stock sound system that auto makers usually put in thier vehicles. But it is in no way a great sound system. I can see an F'body owner, who was meticulous about keeping his ride completely stock, wanting to add the Monsoon system to a non-Monsoon vehicle. But you already bought an aftermarket head unit.
Since you asked about stock speakers, I'm going to assume your using them. In my opinion, the best and easiest upgrade would be to add new speakers. I would start there, and add an decent aftermarket 4-chan amplifier later.
BTW: If your headunit can drive 60W/chan max, You're not going to get very much more power from the Monsoon amp.

