The new ones have both as they solve different problems. The urea DOES greatly decrease regen which helps result in much better MPG>

 

urea is also (from rumors ive heard) 5 bucks a gallon and u have to fill the 10 gallon tank every 5k miles

 

It sounds to me like they have a perfect solution to get you coming and going.

 

Urea is $2.59 ish a gallon and the tank is 5 gallons. It needs to be filled approximately every oil change, which adds less than $15 to the cost of an oil change. It is also a proven system having been used and refined in Europe for quite some time.