Hi there. I just got a new Marquis Spirit Monday. The Spirit is a bit smaller (three seater) but has a few more jets (32 instead of 30) than the Broadway. The Spirit only comes with one pump and I got the upgrade to 160GPM which is the pump size on the Broadway. So pretty similar setups I would say comparing a Spirit with pump upgrade to single pump Broadway.
If you like really strong jets, you will probably want 2 pumps. My wife and I don't like really strong jets so we are happy with ours. When I'm in alone and in the lounger though, I'm turning off every other jet in the spa and getting about the force I like and I could stand a bit more. When the wife is in and another seat's jets are on, the lounger is getting a bit weak. If I open up everything, it's even weaker and I would image anyone liking strong jets would be disappointed.