Having owned the 104.2 for some 5 years now, I wouldnt call them particularly picky. Like most good designs they do respond to better amplification, but, as your experience shows, they will sound decent with even mediocre amplification. Ive run mine with everything from Rotel receivers to a Bryston 4B to a Rega Mira integrated. The most notable improvement from better amplification is in the bass, which can sound loose and wooly if underpowered.
The Cyrus is a good recommendation, though a bit hard to find here in the US. The Rega really surprised me with its relatively low power rating. It did an excellent job (especially for $400!) controlling the bass while extending the highs as well as the Kefs soundstage. Considering that you havent budgeted funds for a preamp, Id go the integrated route for now. Solid offerings from Rega, Cambridge, Rotel, etc... are within your budget.
The Cyrus is a good recommendation, though a bit hard to find here in the US. The Rega really surprised me with its relatively low power rating. It did an excellent job (especially for $400!) controlling the bass while extending the highs as well as the Kefs soundstage. Considering that you havent budgeted funds for a preamp, Id go the integrated route for now. Solid offerings from Rega, Cambridge, Rotel, etc... are within your budget.