Where are your favorite sports-car driving roads in the Northeast? Here's some I came up with...
US 6/202 on the east side of Bear Mountain Bridge if you can get there at 5:30 AM on a summer Sunday. You get to see the sun rise from the vista on top of a few miles of glorious ups, downs, and squiggles. Don't go during the day because it's clogged with slow trucks and other downers.
I discovered I like back-country farm roads. A lot of the southern DE State Roads fit that bill - you can go 70-80 mph and then slam on your brakes for a turn, go zig-zagging through the farms. There are some in western NJ like Sarepta Rd. (upper or lower) where the vertical bumps are just as unpredictable as the horizontal bumps. I don't even drive a sports car, but I love to drive like I do.
Finally, PA 154 if you want to drive an entire route with nonstop fun.
In western Passaic County and northern Morris County NJ, there are a lot of good drag strip/racing roads like Clinton Road in Oak Ridge, and Cannistear Road in West Milford.