I think it's a cost thing as there's nothing wrong with the carbon towers. But there's 2 ways of looking at it.
1) The carbon towers don't break or flex so if you crash the front bulkhead snaps clean where the screws go through the side.
2) The plastic tower might have more flex so maybe less likely to break the bulkhead only if it's not the glass filled plastic. If they are glass filled plastics they'd be pointless.
Then again Durango may want to craw a few extra pennies back per kit and make them standard in the kits and still charge the same price. But if they are it wouldn't bother me it's a good car for the money.
