HI, I don't have an answer for you but oddly enough I see very old posts and I am not sure if this Forum gets a lot of activity.
I am going to look around also, I though I would mention it. But my guess would be the 2.5L for bolt up. I know mine never had great power compared to my ful size truck but I have towed many cars on my dolly and even though I need to go down to third she never left me stranded.