You should wait around for the MSport. They are rare but available. It is not worth the money to convert when the purchase price for used is close to non MSport. I had found a 2010 M Sport Coupe (but auto) loaded for 35k at BMW dealership and it only had 17k miles. Keep searching but if you settle, you might regret it.
On Order: 2015 F80 M3
Current: 1997 E36 M3
Past: 2011 E92 M3, 2011 E92 335is, 2008 E90 M3, 2007 E92 335i, 1995 E36 M3