Not sure what year the in line 6 came out but has there been any commom issues. I've thinking about for pulling a 4500 lbs trailer

 

I6 came out for the 2021MY. It has been available in other JLR products since the 2019MY and has been a very reliable engine so far. The biggest problem I've seen with it on the Defenders is that the coolant line to the turbos tend to get pinhole leaks, but otherwise these engines are very solid. The I6 Discovery is rated to tow 8200 lbs. so a 4500 lb. trailer is nothing. I would try to order one or find one with the two speed transfer case, though.

 

Too early to really tell on the reliability front. Just looking at it and looking at parts prices online, it will not be cheap to maintain as it ages. It is silky smooth and very linear in the power delivery.