Adding an IEC inlet will not help anything. It will only add another point of (I^2)*R (or more precisely, (i^2)*z) power transfer loss. You will not want to put an over-sized power cord on your equipment either, as it lessens the ability of the power supply’s filtering circuitry to reject noise proportionally as the cord impedance drops (ie false economy).
Vintage preamp/amp power cords
Let me just say I don’t want to start a discussion if power cords make or don’t make a difference. I’m just curious to know if folks with older gear with captive power cords mostly considered a replacement with IEC type plug. The power cord on my McIntosh MC2200 is literally a little better than a high quality modern lamp cord, But it’s been there for almost 30 years. The main objective of the replacement would be safety as well as Sonics, if any.