Why do you want a plane that failed?
The M saw very little action and was eventually terminated. The other M prototype became the first N prototype....
First off, thanks for taking a lighthearted thread WAY too seriously- if ya searched, you'd have found probably at least a dozen threads calling for the hot-rod Jug.
That having been said....
I'm curious as to your criterium for failure. It had teething problems (most a/c did), and the entire 47 line was scrubbed in favor of the F4U and F51 by 1948, so I can't really cite the short service length of the aircraft as a "failure" in any means.
What it certainly DIDN'T fail at was smashing speed records belonging to the P-51. 473mph at alt? Yes, thank you. Almost 40 mph faster then the Mustang.
I also don't see why the M/N comparison is brought up. They only share the same engine. Beyond that, they're ENTIRELY different aircraft. A comparison of the P-39 and the P63 would make about as much sense.
**Edit** HAIL ZEUS!