There is no HP limit to a street car. You could take a 1000 dragster on the street, but if you never go near WOT, what's the problem?
Seriously, it's all about practicality. If you can run pump gas, and the car can be driven on public roads (potholes, drive in bumper/bumper traffic for 200 miles), then I don't see any limit. All that power doesn't have to be used, it's up to the driver to stay off the throttle when it's not safe. Each driver determines their own streetability requirements.
Some may not like your car w/ all the suspension work you have done (I am sure the ride is far from a cadillac now). It's too subjective to determine.
Scott