As long as the amp is 2 ohm stable and the speakers are 4 ohm, you can wire them in parallel. If it isn't 2 ohm stable (haven't seen an amp in years that wasn't) you can wire the min series to give the amp an 8 ohm load which it will handle just fine, it just won't make as much power. Another option is to run the front speakers off the amp and the rear ones off whatever headunit you currently have.