As a person that has done a fair amount of HPDE and road racing events with a 95 Cobra.....
The stock spoiler on an SN95 has been measured to delivery ~40 lbs of down force over 100MPH. In other words, it's almost useless and is for looks. Most people add a Gurney flap to the original wing to add additional down force, install a NASCAR style spoiler, or add a full wing to get over 100lbs of downforce on the rear.
I would reduce you're expectation of hitting 200MPH on a road course unless your planning on going down the Mulsanne straight with the chicanes removed and have some serious money into your car. The fastest car I drove at Summit main was a 800+ HP AIX car that was fully setup with aero bits out the ass and a proper
suspension, and I think I might have hit 160 down the straight. That car probably cost over 100K to build. You will have to do some serious aerowork on an SN95 to keep it planted above 150. The front end starts to get pretty light around 130-140 even after being lowered and all the normal stuff done. You run into all sorts of durability and cooling issues on a road course when you start making enough steam to even try and hit 200. And then you have to scrub all that speed off before you enter the corner, otherwise you kill yourself.
You can setup a car to do both drag and road racing, but it won't be the best at either. It can be somewhat good at both, but not the best. You're probably going to want to look at a full torque arm with
panhard/watts link setup as a base, and then have to swap springs, shocks, and tires out when going between events. You're better off setting it up for one or the other, or have two cars like I'm doing. A car setup for drag is downright scary on a road course.
Just for some perspective. This is a video of Brian Faessler, son of the owner of Paul's Automotive Engineering. He's one of my favorite AIX/unlimited class racers I like to watch as he's a great driver and has some serious money into his car. He says he's making 750-800 HP here and has the car built to support it. I wouldn't want to guess how much money it took to get here.