The Sundown and the Atomic is the same AMP the only different is sundown is running on a 3 year old circuit design and the Atomic has updated it design to be more efficient under heavy double kick drum abuse.
Also the Sundowns Subs called the night shade is an Atomic Apocalypse
The Night Shade 12" cost $630.00 retail and comes only in dual 2 ohm or dual 1 ohm
The Apocalypse cost $340.00 retail and comes in single 4 ohm, Dual 2 ohm, Dual 4 ohm, Dual 1 ohm
Also this sub been under the names of Digital Designs, Image Dynamic, MMats juggernaut, Eclipse Titanium, Kove, some U.S.A built Kenwood, FI, SSA, Sundown, and a few more brands I am not aloud to talk about.
Unless the have a factory there just a marketing company!! We all know how marketing company's go under as fast a most people change there socks.
As for warranty problems it is usually the dealer that has not ordered the re-cone kit or sent back the product for warranty. I have been using Atomic for over 10 years and have never had a problem with them at all.
