Velodyne HGS-18 and Triad who makes it Platinum?

I am running a home theater split from my 2-channel system. The speakers used are ALL triad, and definitely need large subs for the set. This is for a theater only, no being concerned about 2 channel. Though I understand the relationship bewteen a good sounding 2 channel speaker/sub/amp and home theater.

I am using a pair of Triad Platinum 18" powered subs now.
Does anyone know who makes these for Triad, assuming they do not directly?

The real question is this:

Would I notice or hear any differences in using a pair of HGS-18II subs in place of the Triads? I have the Triads set up right now, in use, and a pair of HGS-18IIs still sealed. I have the ablility to return them if NOT opened, and am trying to make the determination before doing so.

I like the Platinums quite a bit, however, wondering if a large change would occur by using Velodynes instead.

The amp in the Velodyne is a 1,250 while the Triad is 500.
Is output like a regular amp, where you need to double the power to increase 3dB?

Any help or insight is greatly appreciated.

Thanks,
Dan