The 996 is a lovely looking machine, but it depends what your aims are with the car. 3-4 years ago the 996 would have been hugely cheaper and it's where my money would have gone. With the current prices going a bit crazy I'd be going for the newer car every time, especially if you're planning to drive the car and not get too hung up on future value. That's what I did and I don't regret it at all. As they age the prices of the 996 and 997.1 will start to overlap. While the 996 C4S is arguably more special looking than the 997.1 C4S when comparing to the standard narrow bodied cars, they still made quite a few of them. The values will only really increase once lots have been written off or rotted away in 10+ years.