Picked up a set of mm651's, will one single soundstream 4.520 handle 2 tsd6902r's the polks and the titan xl's or will the 3ohm nature of the polks throw it off?

 

The only way to run it and get max power to those 6 speakers is to run the Pioneer 6x9's and the Titan XL's in parallel, but you will probably be disappointed in the results. You will only have 65 watts going to each of those speakers.

 

I'm going to make the assumption that the Titan IIs are in the lowers. If that's the case, then you're best to change out the MM speakers to a 4 ohm speaker, run the fairing and lowers in parallel on the front channel and run the 6x9s on the rear channel.