Ultimate pedals have good extensions.
http://www.ultimatepedals.com/
Without extensions for the Z4M Coupe, it's going to be VERY difficult trying to heel-toe using the old traditional (use tip of foot to HT). Whoever told you this was easy in a Z4M, obviously have not driven it. With racing shoes, it's already not possible to keep even 10% of my toe area on top of the braking pedal. It's not just silly, it's VERY dangerous on track if you slip your feet trying to rev match.
I am a US foot size 9. Other race cars have their pedals (brake+gas) adjusted closely together so it's not hard to do so. It depends on your cockpit size and pedal adjustments. Street cars like ours, don't have them spaced so closely together because they're not race cars in the first place. AusTTin Bob noted that right in this post.
For example:
Lotus Elise Pedals -
Pic of someone's foot on it.
[u2b]<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/uy9vxvNd1Vk&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/uy9vxvNd1Vk&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>[/u2b]
Ayrton Senna in a NSX (tip of toe to heel-toe)
[u2b]<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/8By2AEsGAhU&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/8By2AEsGAhU&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>[/u2b]
Keiichi Tsuchiya Heel toe technique (base of foot to heel-toe)
[u2b]<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/BLflNPLJ1pY&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/BLflNPLJ1pY&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>[/u2b]
Chill guys. All-talk and flames are crazy in here.