Personally I would pass on the Lightning 2's. I have both the Lightning 10's (2005) and the Marathon Carbon TF (2007). The Lightning 2 was the 2006 model equivalent of the Lightning 10.
You mentioned you wanted a carbon shell, well these don't have one. Rollerblade decided for the 06 year to make the skate cheaper, so they cut out the carbon fiber, replaced it with plastic, gave you a less stiff frame, and gave you 90 mm wheels instead of 100mm. Then for 07 they realized their error and returned the skate to it's previous materials, back to carbon fiber which made the skate a bit lighter and stiffer.
I used these skates for just about everything. I even started racing on them. They worked just fine to start out with. After several races though they really started to lose their appeal. I have since retired them for racing due to their overall weight and lack of proper ankle support/fit.
These skates are not light. They are basically five pound weights attached to your feet. For a half marathon, the weight didn't bother me that much, but once I started doing longer distances I found the extra weight really tired me out.
The ankle support and fit isn't very good either. The padding in the boots are in all the wrong places. I found both skates to have too much padding in the toe box and on the upper cuff, but not enough padding in the ankle/heal area. This caused my heal to consistantly slide up and down. No matter how tight I put the ankle straps, my heal always would rise up. The extra weight exacerbated the problem more. Overall this bothered me a lot. I thought the ratchet ankle strap would help solve this problem in the 07 Marathon line, but it doesn't. The boot is too stiff for the strap to tighten the boot properly.
I still have both of these skates, but I rarely use them. I have since moved on to what I consider to be one of the best all round skates I have ever owned and that would the Bont Semi Race skate. These might be too much of a race skate for you though. They fall into a category between the Rec and Race skates, but much lighter and much faster than rec skates. I would highly recommend these skates if you are considering getting into racing or want to skate long distances. They work fine on rough pavement as well. Although I have yet to really have a skate that didn't work well on rough pavement. Any skate with big wheels seems to work fine on rough pavement.
I hope that helps a bit in your decision on the Lightnings. I don't know much about the crossfire models. I have a hard time getting past that stupid TFS lever on the back of the skate.