I can only speak from experience. I only raced MOD 4WD for 2 months in 2007 due to a local track closing. Week in and week out my 501X never broke, hell it's been sitting on the shelf for the past 2 years with a load of nib A-arms/parts stashed away
. I bought many A-arms due to seeing everyone else breaking them non-stop back then (very rough demanding track). It (501X) seemed to be stronger than the other buggies during that time period. That being said, can't speak about 4WD's I've never seen run like the D4 and some of the newer machines. Keeping it REAL
BTW- My Dark Impact was a joke!! Damn you Tamiya