Didrace,
From the picture the kit looks to be in excellent shape. I would start by taking out the front one-way and putting in a spool or a diff. That will allow you to have much more control under braking. On the other hand, if the track you run at doesn't require much or any braking at all, then stick with the one-way as it will allow the car to roll much more freely. As far as converting your kit over to the RRR Evo, I would start with the shocks, one-piece motor mount and aluminum hex hubs. After that it's up to you if you want to go with the light-weight 2 speed shaft and blade type rear sway-bar. I also prefer the upright position on my throttle/brake servo as apposed to the laydown position.
Regards,
Speyederjedi