"Accelerating to 20 km/h would be a violation of the conservation of energy." Actually it's not. You could do 20 km/h, but for a shorter time. Your not going to get more energy than you put in by regeneration, but you can use it up faster by going faster.

The diagnostic connector in most modern cars has pins on it for CAN bus and some of the other common buses. If you Google the pinout of an OBD-II connector you'll see pins for CAN. There are daughter boards for many popular micros.

When i asked about temperature i was thinking of operating temperature more than curing temperature..

I have plastic interior tools with a flat scraping edge that I like to use for this, but because the cover and the head are both hemispherical channels, they don't work well at all.. Maybe use the corners of the flat plastic tool to scrape it out of the channel?