The sides of the dash should be removed to allow removal of the upper and lower dash, also handy for running wires.
451 Fortwo 999cc
Removing The Dash Sides
Under each end of the dash are a pair of decorative covers,
remove the Torx screw from underneath.
Pull the bottom of the decorative piece outwards to unclip it.
Now swing upwards to release it from the car.
Remove the 3 Torx screws as circled below.
Pull the cover up and towards you to release it from the car.
Now remove the final 3 Torx screws from the under cover.
Pull the cover up and towards you to release it from the car. You will find that it has 3 tabs that hold onto the lower part of the dash but these just pull out as you remove the cover.
Job done, you can now continue on to remove the upper and lower part of the dash,
remove the glove box insert, fit tweeters to their intended position or access the
top of the SAM unit depending on how thin your arms are.