on my 4300, the fenders seem pretty strong. the front end side panels and hood seem ok, tho mine had a crack in the hood when i got it. the weakest thing i see is the cowl between the hood and dash. almost every bolting tab is broken, and it only stays on because of the way it integrates into the dash and lower steering stand.
i briefly debated getting a new hood and cowl (about $450 for the both), but decided that since it is still plastic, one thing falls out of the raised loader bucket, it's gonna get busted again anyway.
definitely would have preferred these panels to be SOME sort of sheet metal!