I know nothing about Tomos, but Moped Bill recently helped my 70s, slow Puch Freespirit (we're talking LOW end - no suspension) go a good five miles an hour faster. So rest assured that if you're willing to put in the work (or find someone to do it for you) you can make even a cheap, slow old moped go a reasonable 35. I don't think I'd even want to do 75, considering that my poor bike would probably fall apart.