DC is ok, the only decent thing they make IMO is their headers. They don't net the most top end power, but they're consistent throughout the power band, and they're 50-state legal. Their other products (i.e. tie bars, braces, exhausts) are junk. Their bars and not designed for anything but show; very little structural integrity.
BTW the Weapon R race header has consistently dyno'd w/ much greater peak power than any DC header on an Integra.
And Razo is a reputable company as well. They only makes pedals, knobs, etc.; interior products.