Thanks Dakkon... What are you using to run it? An AVR or separate amp?
Separate amp, 250W @ 8 ohms 500W@ 4 ohms...
The 180 gets all the power it could ever want... i don't know that there would be an audible difference between an AVR and Separate, just that with the separate the speaker will the extra power it wants if you have a large room to fill.
From talking with Brent, 90+% of axioms customers use AVR's to power their equipment, if the amp section on your AVR is rated for 4ohms, you should be fine. I would try the AVR before dropping cash on a separate amp, I would say only buy a separate amp if you are driving your AVR amp into the clipping region...
here are some photos for you vp-150 on top, vp-180 on bottom.
