I had both, The real differance is in the software. The DL-1 is much more sofisticated. So it is actually a little harder to use at first, but when you have become more experianced it can do so much more. But the most important reason to have Data is to share it with other drivers. You will get much faster by comparing your laps to someone who is faster.

So get whatever is the most common where you race. Here in the Northeast alot of guys run the DL-1, but in other parts of the country it may be different