Hi Robi, If you have basic woodworking skills & tools, and the space & time to do it, then go for it. I believe it would be best to buy plans for a well-designed & established class boat, such as the Taipan or Blade from Australia, they are both F16 class compliant boats,and you can race boat for boat under F16. The Taipan is already present in the US, and the Blade is under construction as a production boat, so you`ll have guys to compete with in the near future. The danger is building your own design - it will hold very little resale value even if it is fast, since it isn`t a class boat, unless you know what you are doing and want to build a one-off to F16/F14 class rules. Rather buy plans, the guys who designed these boats know how to make a fast, strong, lightweight boat. Follow their instructions diligently & you`ll have a fantastic boat. In the Taipan & Mosquito classes in Australia the home-built wooden ply boats are competitive with the glass boats, are as stiff & strong (if not more so) and just as light. And you have the satisfaction of sailing a boat you built, rather than just forked out some cash for.
The attached pic is of a home-built Mosquito in South Africa, and it has won many national championships. The owner bought an epoxy boat, now he & his son argue over who gets the wooden boat !! (The white boat next to it is also homebuilt plywood, could you have guessed?)