What mods does he actually do? It is well known to replace the tantalums and electrolytics.
From the Audio Classic website.
Modafferi Mod
B- power supply - improved regulation, less hum.
RF selectivity improved for better spurious rejection.
IF regeneration fixed - better weak signal reception.
IF 'tailbiting' fixed - this eliminates degraded reception
at 96.3 and 107.0 Mhz from ninth and tenth IF harmonics.
(9th and 10th harmonic, !!!!!)
Stereo decoder slew-rate optimized by modifying op-amp
feedback circuits; reduces distortion, improves separation.
diode D307 installed (this was left out of MR78 but was
used in MR77); this reduces 'klunk' noises on fixed output
jacks when tuner is turned on and off.
IF phase trimming - 'gimmick' capacitors added as needed in
NORMAL IF filter for improved stereo separation.
RF oscillator emitter tap re-dressed for minimum leakage
inductance; reduces drift and eliminates oscillator
pulling on strong signals.
Jung-Marsh capacitor upgrade in MPX and audio circuits.
cardas audio output, midas scope output jacks installed.
Muting ground changed - improved muting performance.
19Khz stereo pilot circuit change, reduces stereo distortion.
Buffer resistor installed in pointer lamp circuit, prevents
lamp heat from burning red light filter material.
Investment: Tuner Approx. $700, Tuner-Preamps Approx. $900
Turnaround Time: Approx. 3 weeks
All changes are not applicable to every unit