So to go over it
AP/Durability
Harley downscales to Batman's feats which are as follows
- 47,614,058 joules or 0.011380032994 tons of TNT
- 908,035,947.2 joules or 0.2170258 tons of TNT
- 1,013,993,071.544 Joules or 0.242350160503 tons of TNT
Superman's feats are
In terms of high ends, the Batman durability feat is 4.65x above Superman's feat. But I'm not sure if Harley fully scales to that either, since she's never given Bruce that level of damage in one punch and he can rather consistent demolish her in a fight. But I will say that she will overall have a solid AP advantage over Superman
Lifting Strength
Harley is at most capable of lifting 545.2 kilograms
Superman can
flip trucks,
lift tractors, lift
large trees,
flip houses and throw tractors
dozens of miles away
The tractor feat alone is 4.38x what Harely can do at her best and that's a young Clark just casually lifting it. The tractor toss gives him strength well over 40 times what Quinn can do. She gets outmuscled and she gets out muscled hard.
Skill
Harley is more skilled than Superman which isn't that shocking. Combined with her AP advantage and the fact that she doesn't really grapple that's a solid contention for her.
Hax
Then it comes to here. Superman:
Finally lets talk about Superman's heat vision.
In a speed equalized setting, this means that Superman's heat vision is something Quinn cannot avoid without aim-dodging, and even then that might be questionable. This more or less means that Superman can counter basically all of her gear without it being much of a threat to him.
Conclusion
Despite everything I said for the above... I still sorta support Harley. Both are in character and doing
something like this just isn't an in-character move for Superman and Quinn's much better skill/experience with her Superman probably just gives him a edge here. Even if Superman has better travel speed, his in character action is to brawl and she just hits harder.
Now he still has win options. If he grabs her and starts to pummel her its likely over, but it'll be hard to do that unless he harms her with heat vision first which isn't something he would do imo.
Basically SV Superman can win, but I don't see him doing so a majority of the time while in-character. OoC he just vaporizes her though.