Since when was slightly superhuman above street level?
Street level means that a character deals with and is threatened by things and people that operate in street level situations. Gangs, mobs, soldiers, and terrorists. Essentially; if the things that normal criminals can get access to can hurt and kill a character if they connect, then the character is street level.
The weapons and tools available in Marvel NYC make Spiderman street level, but a high street level.
Wolverine cannot die because of his HF, but he can still be seriously hurt by weapons that normal human criminals can purchase and build in Marvel.
The turtles' repeated problems and injuries from human characters like Shredder and Karai make it clear that they are street level by many definitions.
Thanks, I really should have written slightly superhuman instead above street level if your definition is correct.