B&W 803N's

[audio amateur]

By generation i meant are they the current model or an older model?
And by 'tight' budget, I meant that you're looking at a speaker that is a lot more expensive than your used maggies. Are the 803 used or brand new from the shop?

As for the 600 series, I've heard people say they prefer the 684/685 to the 683. As you probably already know, the 683 has a dedicated midrange driver, which uses their FST technology (I believe it has to do with the fact that it doesn't really have a surround). And also dedicated bass drivers. Which means they may sound a little different to the rest of the range. If you liked your 684, then I'd say it's safe to go back to the 600 series. But why not try something new? There are so many offerings in the US it's a shame not to.