I always recommend the Grade 12.9 alloy steel screws in the chassis, motor mount, shock towers and shock mounts (basically any high stress area or place where the screw is threading into aluminum). Titanium screws just don't have the same shear strength as alloy steel. You also don't want to thread titanium screws into aluminum. The metals react to one another and you'll very likely strip out the hex socket on the Titanium screw when you try to remove it. The Grade 12.9 screws I sell are much stronger than any Titanium screws you'll find on the market for our R/C application. The only place I would use Titanium screws are on low stress areas such as the radio tray plate, fuel tank upper mount, PT mount, etc. But if you are only doing it to save weight, you might as well save your money and use lighter aluminum screws in these low-stress areas. Titanium costs so much more than alloy steel or aluminum. Personally, I don't see the benefits in off-road as the weight savings is only in grams not in ounces. Plus I'd rather have a stronger screw and finish than chance breaking a screw and getting a DNF. For the cost, you can spend less and save a lot more weight in the Rx pack, lighter pillow balls (if car has PBS), etc. Even a light-weight .030"/.040" body with thin coat of paint can be a good 5-8 ounces lighter than a thicker .060" body with a heavy coat of paint.