or ... be aware that this will actually blow your head off in nearfieldAccording to WHAT HI*FI:
The KEF’s sensitivity is rated at an average 87dB and nominal impedance is claimed to be 8 ohms, though a minimum value of 3.2 ohms suggest that an amplifier with a bit of grunt would be good. We use our reference £15,000 Gamut D3i-D200i pre/power combination for much of this test – its output of 220W per channel makes the KEFs sing. The Rega Elex-R (£950, 72W per channel) is something more likely to partner the R3s and does well too.
According to me:
Usually the budget between amp and speakers are 50-50.
Try a Power / SPL calculator like this: https://www.crownaudio.com/en/tools/calculators#amp_power_required
Listening at 1.5m with a bit of headroom (6dB) and cranking the volume up to an uncomfortable (for me) 90 dBSPL needs 18W of power ...
Make sure any amp you do get has decent measurements (don't know the two above) otherwise you'll get amplified distortion! And you'll be broke. And it will not sound any better than the amps recommended here!
That budget recommendation was old in the 80's too ... electronics are cheap now, good speakers are not