I'm not sure why you think you can't add an external crossover and EQ. What you won't be able to do is add a high pass filter, which means you won't be able to cut the power your Quads use.
That's a nice to have, but not an absoulte. Much more important are being able to set the delay, crossover slope and EQ on the sub.
That's a nice to have, but not an absoulte. Much more important are being able to set the delay, crossover slope and EQ on the sub.