9920 & 9L setup

Yup, i already have the 9920 &9L. Bought it when it went on sale last month. I'm puttin it in an emaxx with the Fastlane machine chassis. Does the 9L hold up well wit 14 cells? Im really looking to make this things insanely fast. I work at a hobbbyshop and it realy helps sell stuff when they run good. Thats why i was gonna do 16 cells. What is your opinions on what motor to get next that will handle 16 cells and be able to run on the 9920? 7XL or 8XL. Thanx again for all the help. Im a nitro guy but i love the Emaxx and beating the nitro guys that come into the shop thinkin there stuff is the fastest.