Of the two I would pick the Hyper 7 pbs. At your son's age, He won't outgrow the hyper as quickly as the mbx comp. I gather he already has some driving experience and might be passed the entry level stage that the mbx comp is considered for, in my opinion. As his driving skills improve, you can hop up the hyper to suit. You can do the same with the mbx comp, but it will never be the buggy the hyper 7 pbs is. It really just handles better and is more durable. It's proven itself to be a racing contender and a good basher as well.