That's sounds scandalous to me.

90 amp fuse? I have an MTX 6500D mono block and it has three 25 amp fuses and it puts out 775 x 1 (@ 2 ohms). This is the size of my amp, not too big, 11.5" x 9.75" x 2.1" I've never seen an amp that can put out more than 2000 watts and it's a ton bigger than that one. Here is the measurements of that one, 9-7/8" (W) x 2-1/8" (H) x 15-3/4" (L).
Who knows... maybe their amps can do that. Doubt it.