The Mayhem does have the best motor and radio of any RTR. Thats were it ends. Im sorry but its the worst driving buggy out of the box Ive seen/driven. One of the guys at my local track asked me what he could do to his Mayhem to make it better... I told him to lift up the motor and radio and slip another buggy under it. Now if your just bashing its OK but for racing on a track I would say stay away from it.
Now the Ravager is just a 9.5 with a bigger motor. You still would want to upgrade the servos and radio. Now is $300 the total your planning on spending? If so your kind of screwed. You can get the TQ kit for about $220 after discouts at Tower but then you need a motor (OS21RG $110) and a radio and servos. Now you can get an OFNA Comp for under $300. Call Ultimate Hobbies and see what price they will give you. You might be able to get it for $250 or less. You can get by for a while with the stock radio but you really need a better steering servo (Futaba 3305 for $35).