its hard to say if its worth it or not yeah the y8 has 2 more hp than the z6 but I wonder how much of that is attributed to the addition of obd2 if you do what I said then youll be running obd1 obviously. Also even though its only a 2 hp difference that is only peak and what the hp and torque curves are doing before the peak is also very important to compare however I havent compared to stock for stock z6 vs. y8 dyno graphs so its hard to say. Id heard a lot of good things from people doing this head swap from a z6. Most of the stuff you need to do is associated with the y8 intake manifold therefore if you decide to use the stock z6 manifold it would be much easier. Hacking the dist leg isnt hard to do with a dremel. If you run accross a really good deal on a y8 head Id do it. As soon as my tax return gets here Im gonna try to pick up one of those heads put teh zex cam in there and sell my head and hopefully break even.
robster