The G+ car comes with both roll centers. Should only really need springs and oil for shocks. Might want different caster blocks and rear hubs for tuning later on. One-way is not a must as it is usually harder to drive for someone just starting out, but it is a tuning option once your skills progess. Don't recomend it for foam carpet racing though. Build the car stock and try it first. I would than ask any local racers what they are running and maybe try changing a few things. Just remeber to change one thing at a time. What works for them might not work for you as most people have different driving styles. All I can say is ask questions and learn the car. Good luck and hopefully we will have another XXXS owner.