If you've raised them vertical, you should be getting a huge deep, wide soundstage. If you aren't, it may be because of room acoustics.
Bass extension can be improved by a) playing with placement, both of the speakers and yourself; b) playing with bass traps if you're suffering from cancellation (a null right at the bottom of the bass range will truncate bass extension; c) bracing the speakers so they don't sway -- do a search for Mye stands, the real ones are pricey for this application but you can make something similar yourself, preferably from metal but oak will do. Mye type stands will also improve imaging somewhat. Beyond that, I think you have to go to a larger model, or add a sub. I gather the Maggie woofer will be available for $1000 in basic trim, it's apparently good to about 40 Hz, but if that's outside your budget a small sealed sub will work.
None of which has anything to do with your crossover question, I know, but I'm afraid the only thing I know about that is that many have reported a sonic improvement with better caps and inductors.
