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.
Current: 2003 E46 M3, 2004 E46 M3, 2015 F30 335i, 2015 F80 M3