The V-173 was built mostly of wood and was fabric covered, and it was not stressed for anything other than proof of concept in terms of aerodynamics and handling. I do not think that it ever went over about 150 mph.
If a developed F5U had become operational? There is pretty good reason to believe that if not for delays due to the exigencies of war (ie development and production was tied up in existing airframes) it could have seen operations sometime n late-1944 or early-1945.
One problem is that the airframe was designed around the P&W R-2000 engine. The engine was fine but it could (would?) have limited the growth potential. If a plan was to use larger radials like the R-2800 then there would have to be significant rearrangement of the engine 'nacelles' plus additional fuel load.
A turboprop variant might have been worthwhile at some point. If the F5U as designed could have achieved the 450 mph expected, then there is no reason that a turboprop powered variant could not do 500 mph. Also, while the climb rate of the F5U as designed was only expected to be 3000 ft/min in Military power, turboprops would have allowed around 5000 ft/min all the way to around 30,000 ft.
Range might have been a sticking point, as designed it was supposed to have a 200 mile ROA with internal fuel, and only twice that with 2x150 USgal DTs. Turboprops would probably have reduced this range without an increase in fuel load, but the lower weight/hp of the turboprop engines might have made up for the weight of increased fuel load.
Without a significant increase in speed over the late-wartime F4U an/or F7F there would be no overriding reason to buy the F5U, as they were already within 10-15 mph of the as designed F5U, and the F4U and F7F were already much longer ranged by a factor of about 1.5x(?). Looking at the drawings that are available, it seems to me that the F5U could have been given additional fuel, but how much without significant changes to the airframe is a question.
One thing to remember is that the F5U was not a lightweight in any sense of the word, at around 14,600 lbs empty and 19,000 lbs loaded. Also, the footprint was fairly large at around 30' long x 24'/33'/37' wide across the wing/tail/spinning props respectively, while the F4U was about 33' long x 17' wide and the F7F about 45' long x 34' wide - both with wings folded. Not sure how the deck spot and hanger space would work out.