A little off topic, but concerning doing the ton.  My first and only time to hit 100 mph was in 1964, on I-94 returning to Detroit after visiting my brother in Navy Boot.  A '64 Savoy, 225 slant-6, auto.  Mum asleep in the back seat, sis asleep in shotgun.  Road open, clear.  Gave it more gas.  A bit more.  Still more.  Rolling at an indicated 100.   8)  A Caddy blew past doing at least 20 mph faster.    Let it ease back down to 70.

It is something you should do at least once.  That you can do it is as good as actually doing it.

The fastest I have had my completely stock 06 S40 is between 80 and 85 for around 65 miles, and got around 58 MPG.  It still had more to go at over 80, but that is more than enough for me on a light scooter.  This is how my S40 became known as "The Little Bike That Could" with the Patriot Guard Riders.  One note...we usually run the open road at no more than 70 for safety reasons and it does that fine with my summer weight at 205 and winter weight with full leathers around 230 easy.
8) 8)

you must be driving in those drunken rain grooves we have.

Find a smooth spot or asphalt and compare the feel.  

With my 98' ( Café Racer ) 103 mph but exhaust and carburator modified.
- Muffler Megaphon
- Air Filter K&N
- Carburator : Main Jet 152.5 and Pilot Jet 55.

Not sure what it will do but I have had it over 85 one time with room to spare. Fast enough for me. I have had bikes that would do well over 100 but never found a reason to do it. 90% of my riding is on back asphalt roads that are 50 MPH or less for speed limits. This bike is perfect.

I think for the most part that there is just a small gain in top speed if all the mods are external, You might gain 1-3 hP with a change of muffler ,carb tuning, and air filter -intake manifold tuning . I have done all of these an find my bike to run 88 any day, and 90 on a good day (perfect weather conditions-rare!)My bike doesn't run but 1-2 mph faster than it did stock ,but it runs smoother and reaches speeds much faster ! which makes it lots more fun to ride! I really don't care if it won't do the ton ! the money it will cost to get there ,(internal mods)doesn't seem worth it for me, it might be different if I was building a Cafe'.

When I was tuning my carb for the HD Dyna muffler, I did a series of test runs on a straight, flat country road out here (It's actually part of the original 1930's Grand Prix circuit!). The road surface is not great but generally ok. I hit 93 mph. It probably had a little more to give but it was starting to wind out, and I found out what I wanted to know. Handling was fine on a straight run. I was more concerned with keeping my helmet on at that stage.

That was on a still day. I weigh 165 lbs, and the bike had empty, 'square-ish' saddle bags mounted. I also shed some weight by dropping the fender rails, switching to the Dyna, and losing the tall risers. My carb mods are in my signature.

I never need to actually ride that fast. But it was really informative to know what the bike can do. I also had a tach fitted at the time so I learnt even more about what rev range the bike works best in (higher than I previously thought). It really lifted my confidence in the bike and made my general riding much more enjoyable. I don't have the tach on now, but I found it a really useful thing to have on there for a while.

I'm not a speed demon. I switched from a Ninja to the Savage partly for that reason. But I do like to accelerate quickly to the speed limit (or thereabouts).

Someone on the forum once put it really well: "The Savage is great fun at legal speeds".