I think kn2600 is paired with psr2100, and kn2400 with psr1100.

You may see Synthplanet prices at:
http://shop.synthplanet.com/index.lasso?stid=synthplanet&from=

kn2600 1416 €
psr2100 1400 €
kn2400 1022 €
psr1100 1038 €