The XT I made in Japan, whereas the Broadway was made in Leige, Belgium. The XT will com with interchangeable Browning Invector Plus choke tubes and factory barrel porting. It will also have a palm swell which the Broadway won't have. If you desire, you can get the XT from the factory with an adjustable comb and they are easier to find in 32" barrels, but these are available in the Broadway if you are patient.
Both are good, dependable, pretty guns in my opinion. I the "made in Belgium" weighs heavily with you, but you like the modern features, look into a Winchester Select Energy Trap. They are made in the same factory that the old Broadway guns were, have the wide broadway rib, but have all the same modern features mentioned above. And to boot, they are a bargain on today's market.
No disrespect, but comparing a Winchester Select Energy to a Broadway Superposed is like comparing a Chevy Volt to a Hemi 'Cuda. The Broadway was a premium target shotgun, was chosen by some of the best competitive shooters in its day and, despite being mechanically complicated, could shoot hundreds of thousands of rounds without major problems. Conversely, the Winchester Select Energy is an economy grade trap gun which has been plagued with broken forends, misfires and various other problems, and is lucky to get through the first 10,000 rounds without a trip to the gunsmith.
The XT is a solid shotgun and is also far superior to a Select Energy.
Look around at any club and you will see alot of people shooting XTs. They are a good value and a great trap gun. Buy a used one in good condition, shoot it for as long as you like and then sell for atleast 90% for what you paid for it. That is hard to beat. Imagine buying a new truck for $40K driving it for 4 years putting a 100K miles on it and then selling it for $38K that's what you get when you buy an XT.