Here is my 2 cents - when you add in "old age inflation", it's now worth 3 cents.

A street car should generally be a car that could be daily driven as it is currently setup, without any changes. It should be a car that you wouldn't mind driving it back and forth to a job 20 miles away from you every day for the next six months in all weather conditions, and it should be at least reasonably road legal. Street car track classes generally require the driver to drive 30 miles on the street in a street legal setup, then stage with nothing more than tire pressure adjustment - no changing maps in the computer, changing fuel source, changing timing, etc.

Tires - they need to be DOT approved, and not bald where you would get a ticket for them, or would be afraid to get on the interstate in the the rain. Hoosier QTPxs, and MT ET Streets are DOT legal, as are DRs, but slicks are not. Face it - it's not safe to drive from Atlanta to SDR on slicks at 70mph. That's a fact.

Fuel - C16 and C23 are not legal by any means - not even remotely close. You can't drive your car 500 miles from home and back, because you wouldn't be able to get fuel. Pump gas, and maybe the exception of VP100 (which is street legal fuel) is what a street car runs. Meth injection and nitrous are technically not street legal, but reality is that you can quickly hook or unhook a nitrous line, and meth injection is not your main source of fuel, so they generally are allowed on street cars.

Air/Heat/PS/PB - Many cars never came with these accessories, and you don't have to have them in a street car. Period. Not having them is a personal choice.

Gutted interior - There is no reason why a gutted interior would turn a street car into a race car. If the owner wants to make his street car more uncomfortable, it's his call.

Cage/race harness - There is no legal reason why you can't have a cage in a street car. A cage does not make the car a race car.

Emissions/Tag/Insurance - Most counties in the US do not require emissions; however, the car needs to have a current tag/registration, and currently be insured to be a street car.

That's it. The speed of the car has nothing to do with it being a street car or race car.