I've read lots of posts about head swaps on 96-98GTs to bring them up to 99 standards in horsepower. I have a few questions. What is the main differences between the 96 and 99 heads. Are the heads worth replacing, or can they just be rebuilt. I'm planning on doing this mod next winter (while the car is in storage) but if I get get the stock heads ported cheaper than buying new ones, that might be the route to go this summer. Anyone have a site that explains this stuff? The heads are about $1300CDN each here, Im sure I can get the stock ones ported for less than that. In your opinions what is the cheapest route to go with this?