I love the MK2 and have purchased the accessories offered by Drac, but installing this barrel has seriously improved the blaster!
While there is an increase in fps and accuracy, the real benefit of this barrel is when you're using less than perfect bamboo or DZ darts.
You will no longer experience darts falling out of the barrel when the MK2 is primed, which makes it worth the cost/time to install, however, the blaster now feeds and shoots worn darts far more reliably!!
100% satisfied!