Kept it as it is engine wise but offered two flavours.
spec as is
M3 'Clubsport' package
No sat-nav, iDrive, M-drive
sharper steering rack
19" CSL wheels
Sportier front seats in suede/cloth ala M3 Vaders.
Then, both typical types of M3 buyers would be catered for and you'd catch more people because neither would be as likely to consider alternatives.