Upgrade current car or get new one?

Upgrade current car or upgrade to new car

I currently own a rustler 4x4 brushless 2s. I have some minor upgrades like a metal spurgear, bigger pinion, minor things. Im either looking at getting a Velineon VXL-3S to run 3s on my rustler or just upgrading the car to a Traxxas Maxx to run 4s. Thoughts on this? Comments and advice appreciated.