To answer questions in a couple of posts above:
The tank is a bladder that is contained in the cheek cowls. No vents required. The makings for the tank are included in the kit. At first I used balloons, but now I am into re-configured plastic bags. The tank is just an air free holder for fuel, no pressure is used. There has been an extensive thread on construction and use of balloon tanks in this forum if you do a search.
The kit is pretty expensive, I admit, but it does include all hardware except the engine, lines and handle. Tank, wheels, bellcrank, horn, all included in the kit. A small model such as the SkySport has the same number of parts as a "big one" does. Laser cutting is pretty time consuming, and cutting a 1/2A kit isn't any faster than a big model. The laser machine is pretty costly, and uses a lot of power. It seems to me that Eric charges something like $40/hour to do cutting for others (you would have to check with him to get the correct number, as I am working from memory here).
The differences in the second version are that the nose is 3/4" longer to both provide better balance and more volume for the fuel tank inside the cheek cowls and the change to tricycle landing gear.
I think the resulting model is worth it if you fly competition 1/2A. Several national champions have flown the plane and approved of its performance. Tony Naccarato even says it is better than the 1/2A Pathfinder!