Instructions inside,but here they are anyway. Left to reverse,right to drive. The pixel effect is to reduce lag,the non-pixelated version is remixed. If it is still lagging here,go inside the background sprite and make the pixelation effect higher. (101 most sensible limit)
Google for BMW M3 sketch. Warning! May cause blurry vision. If it does,try non-pixelated version. Link (even if you don't need it): http://scratch.mit.edu/projects/39445922/