If you want a reference quality amplifier with active crossover and price not much higher than MQ Quart, look at PPI Power Class amplifiers. Having said that, I am using MB Quart REF4.80 myself for a bi-amp front stage. Since I have bi-amp crossover setup, I don't care that the REF4.80 does not have a sophisticated active crossover capability. However, this little amp does put out a good amount of power. It's rated for 4x80 at 4ohms, but had measured 4x110watts at 4ohms in an independent test, and also showed very low noise/distortion numbers. I couldn't resist buying one for $120, even though it's MB Quart, a brand that recently seems to get less respect than previously.