The Rustler VXL is absurdly fast with a 3S Lipo in it and in general needs only minimum upgrades. I use mine for street runs with a set of anacondas and run talons in short grass/dirt. I love watching it fly across short grass/dirt fields. Its kind of ridiculous.
I have aluminum steering blocks and stub axle carriers as the originals broke quickly. Also put on an RPM bumper. Dremeled the chassis some to fit a bigger battery.
It doesn't handle real well offroad through. Got my but kicked by a 8th scale nitro buggy over dirt and rocks in a general bashind session, but embarrased the same car on the street.