To get to the crossover parts on a Maggie, all you have to do is unscrew the panel that has the connectors on it. The panel lifts out, and there they are.
That being said, I would be cautious about changing the crossover on a 1.7. I've seen the circuit and it isn't a conventional crossover, but a single pole 2.5-way series crossover. A single pole series woofer/tweeter crossover must be used because it's immune to amplitude variations caused by the falling impedance of the supertweeter segment. Replacing components with components of identical value should be OK, but altering other parameters could ruin the magic of the speaker.