I used Typing Master for a while (but I don't have a licence for it now). It's QWERTY-centric but after the initial lessons that won't matter so much. And it's very focused on accuracy!

You should strive for nearly 98% accuracy I believe. Yes, that means slowing down so you have a chance to learn the right way in your muscle memory! If you're used to typing fast and sloppy that may feel uncomfortable indeed. "Grasshopper, you must unlearn what you have learnt!" :)

I don't seem to get my own speed to more than 75 wpm myself. Guess my brain just isn't that fast. But typing more accurately helped me a lot both with speed (used to be around 60 wpm) and comfort. It's so much easier to "think with your fingers" when you don't have to correct a bunch of mistakes all the time. I still haven't given up my 80+ wpm ambition.

To get to 100+ wpm I think you need more than just accuracy! Look up Ryan Heise's story; he explains part of what he did. At those speeds you should know how to type many common words really fast instead of just typing each letter separately, for instance.