Wow! You mean to tell me those diff gears won't wear down? I know I had mine for about three years at least, and haven't changed the diff gear yet. So EXT2Rob, you don't know of anyone that has worn down the metal diff? That's reassuring. I like having back-up gear/parts for my "toys".
That ZD Racing Truggy was a blast to drive, but my track is only about 8.5'~10' wide with lots of turns. I did run it in the grass, but mostly straight runs. Like I said before...I gave it a shot...1/8 4wd is not for me. Too big & too fast, and too expensive.