Obviously, FM tuner sensitivity is not directly affected by power supply. But since Naim use interconnects to carry both signal and power, the use of a Naim power supply and/or tuner head that has not been properly prepared for use in north america will affect performance (see Yank's post).
When I lived in the USA and Canada I had Kenwood, Yamaha, Luxman and various other 'top' tuners, and to me the difference remained then, as it does now, between capturing signal and reproducing sound. One huge difficulty for the north american 'judges' of world tuners is that the broadcast signal of most US/Canadian FM stations WAS (i can't speak beyond the mid-80's) compressed compared with the signal put out by, say, BBC Radio-3 (at least during parts of its schedule).
I am not comparing statistics - i'm comparing actual peformances, and point out how potentially flawed so-called 'objective' tests may be.
British tuners of the 1960's-70's had an ability to bring the listener closer to the source than anything i know of out of japan or america. this was likely due, at least in part, to the close working relationships between BBC engineers and workshops and firms like Garrard, Armstrong, Quad. from the 1980's, Naim achieved a new peak.
I have not owned a Linn Kremlin, but i have listened to one. i have owned a Linn Pekin, and run it side-by-side with a Nat-05, Nat-01 and Nat-101.
whatever the specifications say, the difference in performance is 'night and day'.
Skyebridge