One of the 1/8th clubs around here races on grass using a temporary track that has a different layout each meet. I've been there a couple of times lately with 4 of the other brushless truggy guys. Anyway most of the truggy guys are using these tyres.
http://www.hobbypeople.net/gallery/149932.asp The first time I used them was halfway into the race day after another brushless guy broke his diff, so he let me borrow these tyres. Straight away I was a lap and a half faster than with MT crime fighters. I haven't used badlands, but the ones I have seen ballooned a fair bit, and weren't as responsive, because of the big side wall, plus I would say they're heavier.
There slightly shorter, so you might need to adjust gearing a little if you want the same top speed. You also need to use the hyper ST style rims, because instead of a vertical bead, they have a horizontal bead (seems to hold much better).
Rims:
http://www.amainhobbies.com/product_...h-Rims-White-2
http://www.amainhobbies.com/product_...-Wheel-White-2
http://www.amainhobbies.com/product_...A-Rims-White-2