QC, I'm an engineer, so I just can't help it...

Here's a video of a faired SV650S hitting 143MPH at the redline of 11,000 rpm.  Also logical given the reduction in drag.

https://video.search.yahoo.com/search/video?fr=yfp-t&p=SV650S+top+speed#id=2&vid=d83d953c23be71b1aae134b566c6cbba&action=click

First off, I think something's a bit off here. My GS is stock and just last week I clocked a whopping 195 KPH (about 120 MPH) with a GPS on it going on a flat road at 9.5K RPM...and the bike has about 105000 KM on it's original engine.
I've seen A Twist Of A Wrist two times actually. And no, my fun isn't in the high revs, it's just that the GS makes most of it's power there so when riding on twisty roads I tend to stay above 7K RPM. It's just the bike's nature. When I had my dad's VN900 for a couple of days I didn't push it past 100 KPH because it didn't feel like it wanted to go there and plus it made most of it's power down low so I really had no reason to push it. If the SV's sweet spot is in the mid range then there is where I'll spend my time.

I actually spoke to my friend who has a CBR650 and used to ride a GS too, very aggressively at that. He said that he realized that riding the way he did on the GS might get him killed so he took it down a notch and now he might cruise at a different speed but he doesn't take dumb risks anymore. The key phrase was "if you have experience and a working brain, and you do, you'll handle 75 horses fine, just know your limits".

Tundra, I've seen the GS500 top speed reported from 95 to 112 MPH, as a function of faired / unfaired, mods and tuning, and size of and ability of the rider to tuck in.  A large rider makes a real difference here both as to weight and the wind drag they impose, as a big rider could be over twice the weight and have nearly twice the frontal area of a small one.  However, I've seen no other report of any rider getting 195kph = 121MPH out of a GS500 on level ground.  I suspect error in the GPS--mine is often 200 meters off in reporting position.  Another possibility is the wind, as a 10MPH tailwind could add about 7 MPH to top speed.  So, some combination of GPS error, rider size, wind, and slight downhill grade could explain it, just as having those factors working against you might explain 95MPH.       

Here is a video illustrating top speed of a GS500E, which if accurate is probably a small rider that is fully tucked.  It shows 173 kph = 107.5MPH at 9500 rpm.  The engine won't go any faster as it has reached a balance with increasing wind drag and declining horsepower at the very high end of the RPM range. 

https://video.search.yahoo.com/search/video?fr=yfp-t&p=GS500+top+speed#id=3&vid=5448923dbdd3ae3bd9f1223961c748e6&action=click

From what I've come to know, the GS is set up differently around the world for different emission standards. In the US for example it's tuned too lean and people advise a rejet to get it running properly. Here in Israel it's probably tuned differently, plus I put a small windscreen that helps reduce drag substantiality and fit quality radial tires on it. IDK how it got there, it usually doesn't go past 180, maybe the road wasn't as flat as I thought.