It will fit - I have the 400/4 unit on top of my Sony head unit. The 400/4 has the same height and depth dimensions.... and the 400/4 is wider. JL Audio makes great amps.
His - 2012 RGC, Vivid Black, Bassani RR II 2>1 exhaust, Ohlins, Traxxion, SE breather, Dyno Tuned, JL audio
Hers - 2013 Deluxe, Birch White / Sunglow Red.