I have an AKRA EVO on my E90. The slips on's are specific. If you purchased slip ons for an E90, the bevelled ends of the pipes that would meet your x-pipe will be adjustable and in your kit will be 2 adapters you'd slip into the end of the pipe (you'd actually have two clamps about 2-3 inches apart holding the pipes to the adapters, and then to the x-pipe). E92/93 are the same length and will not come with adjustable adapters to meet the x-pipe.
Not running an M at the moment........I stress "at the moment"