Ill put my 2 cents in,
I am 16 and iv ben rideing 4 weelers all my life starting when i was 2 with a 50cc andyhow i reacently got a raptor 660 and everybuddy told me its was goint to be a wild 4 weeler and all this 3rd gear weeles and when i got it i was expecting alot more. It really depends on how well you'r son can handle his quad. I would probly say the 350 raptor tho because they are alot more reliable.(warriors) I would then go with a 660 If he wanted more because the raptors are better for the woods driveing and are also good quads. Thoes 450 are fast for only 100 cc more. The 400 EX arnt bad eather my bro has one and its defentaly realibale. ill give it that.

 

hey i just got a 350 for my son who is 13 also and he operates it great

 

I got his age mixed up he is ging to be 15 monday. I hope it's not to small for him.

 

i know i was talking about your 13 year old the 15 year old will grow out of it in a little probly it is a good fit for a 13 year old kid and my son is smaller type of kid for 13 also