parallel or serial wiring

Ok. I sent back my rubicon 450's because they wouldn't fit. I'm going to try out 4 of the fusion 6.5 inch speakers. They handle 150 watts each. I have a 2 channel amp that puts out 300 watts rms x 2 @ 4 ohms or 500watts x 2 @ 2 ohms. What would be the best way to wire these using this amp. If I wire them parallel would that still be 4 ohm? The amp is a MA898? or do I need to get a 4 channel amp. I don't have the speakers yet, but if I can I'm going to go with 6 of them. Of course then I'll need another amp.

I'm assuming that your speakers are rated at 4 ohms. If you have 4 of them and wire 2 of them in parallel to each side of the amp that will bring you down to 2 ohms on each side and get the most out of your 2 channel amp.