Replacing the stock 2 conductor power cable on my Nakamichi 582 cassette deck?


I am thinking of replacing the stock 2 conductor power cord that came hard wired on my Nakamichi 582 cassette deck.
So here is my question.
Should I just replace with a much heavier gauge of cable and leave in the 2 conductor non grounded as OEM supplied configuration.
or should I replace with a 3 conductor and add a ground and if so where would be best to add it at the cassette deck end? Or would that be a move that may actually induce some type of ground loop/hum?
Thank you and Merry Christmas!
128x128uberwaltz
@jea48 
I was sort of thinking if it was designed to work fine without the 3 wire connection, then adding a ground could be more harmfull sq wise which is part of the point of asking for more expert advice than my own. 
So with that being said I could at least investigate the possibility of adding larger gauge power cord, I would not be too worried about enlarging the hole in the back a little. If I use a rubber grommet it would look very similar to stock anyway and for what I paid for it I will most likely not part with it.
Or your idea of adding a male IEC connector could be done but if I cut the original cord down to approx 6 inch surely that would have a similar effect on potential resale value as well?
Not that I see that as any issue to myself tbh.
As far as polarity excellent point and one I have already verified but always a valid starting point.
Dont get me wrong the sq is pretty good but does not mean it might not be better still with a better power cord.
Post removed 
@uberwaltz 
Did you ever change the power cord? I'm wanting to do the same thing on may Nak CR4, I'm really curious to see if changing the cord makes a big difference.
No I did not go any further on this matter...yet...lol
Had plenty of other changes keeping me busy
Before reading this tread I wasn't sure if I should go with a grounded cable or not, but now I know to go with a non-grounded.

I think I'm going to try to put an AUDIOQUEST - NRG-1.5 C-7 on mine, it may take me a couple of months to get a round to it.  If I bet you to it, I'll let you know what happens.