My P-38 would have an EFIS display 
So will my scale P-51 if the insurance premium for the hull alone wasn't equal to my annual operating budget. 
That'll get you killed. If you do decide to pursue an instrument rating (I would highly recommend it) the most important thing is to keep current. The next is to know your limitations and stay within them regarding weather conditions. You'll learn a better understanding of weather, forecasting, decision making and above all a finer level of aircraft control. You'd be foolish to get the rating and never intend to use it much less keep current.
i would keep it current....with a cfi. i tend to fly with bob whenever he has time...even if i feel i don't have a need to, i do it anyway. no matter what, i ALWAYS learn something from him.
i would practice it, i just would probably not delibretly go up in ifr conditions, as that tends to tkae the fun out i think. i was thinking of it to increase my ability in general.
aas for knowing my limitations? i have a reputation in our flying club of actually adhering to them. when i make an error, it;s on the side of caution. everyone that knows me knows that....and when the day comes that i do end up having to land somewhere besides an airport, and i say it wasn't my fault.....those that know me won't doubt me.
you're bringing up your stang again.....how;s it going with that? i'm frakkin jealous dude....