I bought my son his first MTB a GT Aggressor with a Suntour XCT DS (80mm) fork. I knew the fork would need to be upgraded but I'm starting to think sooner rather than later. What a good low cost air fork option that's available with a straight steer tube. My son is very light so he doesn't need anything really stiff or beefy. I would not be opposed to going to 100mm or even 120mm of travel.