Probably o.k. at out of the box speeds. Arrma website rates it at 50mph optimum surfaces. On flat mowed grass, probably low 40mph range.
Website parts and option parts does not list any option shock springs to soften and absorb vibrations at speed. Shocks listed come with 500CST oil-which works out to ~40wt. If you find the Typhon bouncing on its runs, maybe try a lighter oil WT, 35 or 30WT (350-420CST).
Speculating here, my runs on grass are made with an MT10. Hope this helps. Have at it and watch how the Typhon performs for you on that surface. Let us know, o.k.?
Tires don't have a lot of sidewall to flex and absorb surface irregularities. How soft are the tires? If they are hard compound too, that will contribute to more bounce. Perhaps a different set of tires more suitable for grass? Don't know your locale-maybe ask your local hobby shop? 'AC'