The Engines That I Would suggest would be a RB C12 Engine, It is a Pullstart and Its a great engine. Also for better tuning and life you could look into the O.S. 12 or .15 CVR-X. I would take the O.S. Because they are screamers and they live along time with a correct tune. The Dynamite engine you are suggesting is a little less powerfull than the Mach .15 that you originally had, IMO. I Would keep the stock pipe on the car, Because it is a decent pipe. Then For making it handle better, Get a JR 650 Servo for the steering, The throttle servo that comes with the NT is pretty nice for doing the job. The last thing i would do is get an Extra Rear shock tower, It broke on mine easily when i had/ was into stadium trucks. I Hope you find your right gear! ALSO: Stick with the stock Radio, I love it, I still have it on my Mugen buggy. Later
-Skyline