Is Maggie 20.1 still overall better than 3.7?

They cheapened the Maggie's and took away the easy tweets one could do with the outboard XO !!  Less bass is never good no matter how hard someone may try to convince you.  Parts are crap now as well...I've moved on!

Danny Richie (GR Research) just took in a customers Maggies (I think the SMG’s) to redo the x/o with better parts. While he was at it, he took measurements, and found a simple way to improve the speaker’s response by adding a part to the x/o’s low-pass leg, which resulted in a reduction of the lower-range panel’s excess output above the x/o frequency, ridding the speaker of a hump in it’s frequency response. Danny is quite the x/o authority, being hired by other speaker companies to design x/o’s for their products. Anyone wanting their Maggies improved, call or email him and see what he says.

Hasse, by all means, try the SR fuses, and skip the reds and go with the SR blacks.  I'm going to go from red to black.  I also push the amperage values quite a bit--double.   

REL subs integrate perfectly and lift Maggies in sound stage and dynamics--i use two Strata III's. Older, but a nice size for the 3 series. 

I concur. REL subs are the best, IMO.
Integrate seamlessly w/ any system and really adds another dimension
in musicality. Happy Listening!