Hi
@guerney . Good question! Making this conversion safe & legal is our priority, which is why we're building up a network of shops to help as many cyclists as possible transform their bikes rather than just the DIY enthusiasts.
Our controller has two power map modes; regulating the power based on speed & load. One is 'Eco', one is 'Boost'. Both are legal within the 250w nominal rules & speed. However, both modes have a little spare capacity under the legal limit. Pressing the 'boost' button takes you up to the legal limit, much in the way it works on VanMoof.
Yes, the kit functions without the button. We also have apps in the App Store & Google Play (search LaVita Boost) that can use your phone as a display (via bluetooth) and Super-Boost button. The kit is autonomous though so doesn't need a wireless display connected.