I'm going to stick my neck out here and tell you to grab an aftermarket BB kit.
However like Brad said OEM kits for this particular model are a really good price (compared to equivalent Stihl or Husqvarna OEM kits) and top notch quality.
On a stock saw you'll see little difference in performance between OEM and aftermarket BB but if you ever plan on getting some porting done definitely grab the OEM Mahle. If left stock don't bother modifying the muffler either. It will just make it louder
I've put 1000's of hours on these saws (I've owned four of them - still have two) and have had very few issues. Like others have mentioned grab an OEM Heavy Duty filter kit from a sponsor such as Edge & Engine. If you decide on an OEM Mahle kit Edge & Engine are also excellent. If you need parts also contact them. I have IPL's and workshop manuals if you need them - send me an email if you do.
I've had three of these saws ported by Brad (blsnelling) and can certainly recommend his work. Zero failures in a work environment and still pulling good compression after many many hours.
EDIT: Just read that Edge & Engine don't do internet sales anymore. Does anybody know why? Dealer rules?