As a Grasshopper owner myself, I would not say it is suited to "go fast" or "jump things". It is a lot of fun to drive but mostly because it's nostalgic and handles like crap.

If you have a hobby shop near you, you should go look at what they have on display. Things have changed in the last 15 years. If you still want to build something, there a few options. You'll mostly be looking at something ment for racing or a car/truck from Tamiya. As a suggestion, you might take a look at an Axial Exo.

I will tell you while I have several race vehicles and race most every week, my favorite car is my Tamiya Lunchbox. It's just a hoot to drive.