If you have the nuoh and flash for rear speakers, they should work fine. They won't be very audible unless you fade to them pretty heavily. By the way ... where did you mount the XM module? Folks here have siad that the XM module hits the outer fairing when installed on top of the iPod module. Be interested in your solutions.
I have the boom audio rear pods, but I put 6.5" speakers (replaced the 5.25") and put an Arc Audio amp in the Tour Pak (driving the rear pods only). Front fairing speakers and lowers are MLK-165 Hertz (fairing) and HCX-165 (lowers) being driven by a Rockford PBR300x4 in the fairing. Fade control with TP installed goes from fairing to lowers/pods - with TP removed fade control functions from fairing to lowers. All Tour Pak connections are quick disconnect under the seat.
Front amp is using rca-outs done by Tony at Iron Cross - rear Arc amp is fed from rear speaker-level from H/K head unit. Just got everything fired up today and it sounds pretty damn good
I'll post full mod pics once everything is back together.