I did the Rockford PBR300X4 as many others have done. Can get it around $150.00 on ebay and Amazon. Very happy with the amp. It does only run 4 ohms. It will overheat running 2 ohms per Rockford tech.
I went with the biketronics 6.5" speakers for the front made by Hybrid Audio Technonlogies. I got a price match from Eastern Performance on them. They wanted $229.00 but match another price quote of $199.00 shipped. PM me if you want more info on that. Those speakers are a little pricey but include the mounting adaptors and have a lifetime warranty. They sound excellent.
I put the DXi650 Polk 6.5" in the rear pods. They are shallow enough to fit without any mods except to drill 4 new mouting holes. No cutting or adaptors needed. They also sound good. I was suprised by the Polks. Also put poly fill in the pods and Dynamat in the fairing.
I bought the mounting bracket from email@example.com
which is very nice and allows you to mount the amp on top of radio and moves your CB and/or XM radio modules below the radio.
Good luck with your project.