I agree with almost everything our sage writer said above.
We all like to improve things from what they were back then. 50s Speedster, you say?
We have more power, better brakes, better tires. Most have added some anti-sway. Some have even(gawd!) changed the swing axle for IRS. How about that rack and pinion steering?
My point is we are all at least a little bit AWAY from the "original" experience.
The real question though: Where is our own personal line drawn? Is it radial tires? Disc brakes? IRS? Crank-fire ignition? 5 speed?
Or is the line EFI? Or the biggest line of all, gateway to all disconnection: drive-by-wire?
Glad you asked, D! I gave it a lot of thought in my Spyder, which is one reason it has "only" 30 percent more torque than an original. Every gear in my car gets you to about the same speed at redline as the same gear did in an original 550—40ish in first, 60+ in 2nd, 104 or so in 3rd and about 140 in top. But in my car they all come a little quicker—about 6 seconds to 60mph instead of 7 seconds.
And of course my engine's redline is 6000 instead of 7500 as in the 4-cam motor. So not quite like the original experience. But pretty close, I'll bet.
What else? Improvements! Dual circuit master cylinder plumbed to 4-wheel ("barbell") disc brakes. Radial tires with a summer compound—and they're quite a bit wider than the original 16s were (albeit much narrower than what most guys run).
These are just about the bare minimum things you have to alter from OE if you plan to drive these cars on public roads.
Is a crankfire ignition a bridge too far? Given what Rainer Cooney's doing with his replicas, I doubt it. EFI seems to be pretty agreeable to you and some others. I know I wouldn't hate it!
Drive-by-wire though...for me it would depend on the feel. If it felt the same as a throttle linkage (original Spyders had a rod linkage to the accelerator, didn't they?) I'd say go for it. The Morse cable is already "incorrect."