I have that amp..the 150.4,its very nice/small, and clean sounding.Im not running it do to needed more power for my setup in the truck,but its a great amp.PPI Phantom 900.4 is a great series amp for mids and highs,and has gotten excellent reviews,and is a small footprint as well.PPI has been around for years,and have always been a great amp.But for certain, Id run that American Bass mono amp for sure,.Either amp is a great choice for your setup.Id choose for my budget,and what Id like to have.But Both are worth the money in my opinion.