yes, there are many difference's between
the L5 is basically like the first generation L7 we introduced in 2000, with the exception of a steel basket over the aluminum one we had.
Now the new L7's will handle more than double the power, more Xmax, different cone, and the 2004's are a whole new breed of L7 over the 2003.
So if you have medium power, the L5 is awesome, plays in the same enclosures as the L7. But if you have more power to add, the L7 is the logical choice.