£4000 would buy a very good pair of active speakers with amplifiers built in that where chosen to work perfectly with the speakers, just to suggest something different for you to think about.
Adam http://www.adam-audio.com/
Genelec http://www.genelec.com/ or one of the many hi-fi brands, all good fun
An old thread : http://theartofsound.net/forum/showthread.php?t=6856