its basically the same engine, just a bit larger. like i said, those are great engines, but u wont see a huge jump in performance, just alot easier to start and keep running. although HP numbers dont really mean anything, they help a lil when i am trying to explain things. to give u an idea:

the 15FE thats in the car now puts out about .40hp
the .12CV puts out about .50hp
the .15CV puts put about .67hp
the .12CVR puts out about 1.05hp
and the .15CVR puts out about 1.25hp


so u can see the huge difference in the cv-r models.