Truthfully I would have said stay with the 3.55s and do other performance mods. The 3.55s aren't a bad gear. I can spin first with out issues, get a big chirp out of second and I even chirp third sometimes.
I'm totally with this.
OP, what year is your stang? I ask because the 05-06's came with 3.55's, but they changed em up in later years. In 07 I believe they dropped em to 3.23's (or something), and then 3.73's with the newer models. I love my 3.55's because they allow me to do different things. I track my car (road course), play around on the street, take road trips, rip around a mountain road or two on the weekend, and drive her to work once or twice a week.
It's all subjective, but relatively speaking the 3.55's give me great gas mileage, acceleration and top-end.
I know a LOT of people love the 4.10's. Not knocking em at all. People love em because they allow you to accelerate faster, and that's what people want in a street car going from light to light or from 20-60, 35-80, etc. What is your driving style? Any of what I mentioned above? Do you DD your stang?
Honestly, I'd go with an aftermarket, one-piece aluminum driveshaft. That will get you faster acceleration, slightly better gas mileage, and will actually free up a few ponies at the wheels. You won't lose any top end.
However, to answer your original question: remove the rev limiter with a tuner, or have a shop do it. This will allow you to reach higher RPM's, therefore higher speeds. Just keep in mind that we don't have "import" motors that are ok with 8000-9000 rpm redlines.
Hope this helps.