tbh, not a lot of people around here mess around with concept amps. I think your best bet might be google or just do a search here to see what pops up. I tried google and not much popped up though
In my opinion, the Concept amps are just fine. I've played with the CD 3910 for about 5 years. As far as the 1 ohm mod. Amp Medics in Florida can do that for $75. It doesn't make any more power at 1 ohm. But, it will play fine at 1 ohm.
On a 16volt system I've clamped 114vac and 34 amps at 2 ohm. We were pulling 495 amps of current.
Its the same board as the visonik vx4000d and ma audio hk4000d so search for those amps being modded. You'll have better luck searching those. I had the resistors to take out on my old pc but that computer is fried.
I had the cd3910 btw, it is a BEAST! Be sure to have lots of current it is power hungry