Did 125mph(201km/h) driving on I-90 to Chicago in my MX-5 Miata before I supercharged it. I'm using the MX-5 Miata as an example as it's very close to the MR-S in terms of horsepower, which pretty much determines your top end speed unless electronically limited.
Mind you that that was done on I-90, which is a VERY long and straight interstate highway, and it still took quite a while and most of the straights to get it up to that speed. We simply do not have enough straights in city streets 2 do 200km/h in a 138HP MR-S. In a much higher-powered car, maybe.
However, if you're a true sports car enthusiast, you shouldn't even be obsessed with top speed, cuz a sports car is NOT about top speed, despite what the magazines tell you. Top speed is only about speed in s straight line, which is no fun. Top speed numbers are only used to sell cars and magazines to enthusiast-wannabes and poseurs, not true sports car enthusiasts.
A sports car should be about being out there carving corners at the limits with the top down and the wind in your hair. It's about the thrill of rowing though the gears, revving your engine speed to redline each time before you pop the clutch and snick the shift knob into a higher gear.
It's about carving bends and corners at break-neck speeds, the satisfaction of heel-and-toe downshifting: stepping on the brakes and popping the clutch whilst blipping the throttle to match your engine speed and flicking into a lower gear, and experiencing the g-forces whilst accelerating out the corner.
Important rules for sports car buyers:
1. NEVER buy anything other than a REAL manual transmission. By real, I mean one that actually comes with a real stick-shift and a real clutch. 50% of the fun in a sports car is found in the shift knob and the clutch. For the life of me, I can never understand people who buy automatic/"assisted-manual" "sports cars", cuz to me, they're not sports cars at all. To me, it's like they're paying full price for the car, and then flushing half down the drain.
Any monkey can put his right foot down on the accelerator pedal and floor it. It requires absolutely no skills at all. What fun is that? Think about it: if you're letting your car do ANY of that fun stuff FOR you, how much fun could there be left??
2. For performance upgrades, look to getting a supercharger or an engine swap. If you know how turbos work, you'll know that NO MATTER how well managed, you'll still get SOME turbo lag, ANY of which is no fun at all in the corners. Only superchargers and engine swaps can give you linear acceleration.
3. Do NOT be a poseur. I see all those riced out abominations out there with their bodykits/skirts/huge spoilers/fart mufflers/jumbo decals/super-sized wheels/neon lights, and I wonder what goes through their mind. Too much of the pathetic "The Fast and the Furious" in their blood??
First of all, those things add weight to your car, which adversely affects the performance and handling of your car. Especially big wheels, which adds unsprung weight...and you definitely don't want that.
Secondly, no matter how you think it accentuates your individuality, or how good you think they look, they're ugly and BENG to anyone except bengs/lians, unless you can make them look tastefully stock. However, unfortunately, most bengs/lians tend to think that their cars look tastefully stock. More unfortunately, most bengs/lians do not realise that they are bengs/lians. Proof that money can't buy taste. Do yourself a favor and put that money towards performance upgrades, so that the rest of us wouldn't be exposed to such eyesores.
4. Put the top down! For God's sake, you have a sports car! I see so many sports cars in the streets with the top up, even in perfectly beautiful weather. Pretty much defeats the purpose of getting a sports car/opentop. *Sigh*...we are cursed with way too many poseurs around...