Polar Rabbit

New to this forum hoping to have some good advice thrown at me.I currently have a merv running a cc mm big block setup on 4s lipo and the car is stupid fast but I am getting bored and want to go back to nitro. I am looking at the hpi rs4 3 evo and have read great reviews but I like speed and would like to upgrade motor,pipe,header etc.and would like some suggestions as to what I should go with also what about tires and servos?Any help on this would be greatly appreciated.Thanks Polar Rabbit