What are the differences between the 2008 Cabrinha Contra 3 vs 2007 Contra 2 kites if any? Was there a vast improvement between these two kites or just subtle changes...

Well..the 2008 model was built a lot better than the 2007 model..
The hole in the bar was bigger on the 2008 compared to the 2007 model, making it easier to move the bar while turning.
Also supposed to have less barpressure.

But both kites got pulleys on the bar, I recommend trying the Crossbow IDS instead (but I guess you are on a budget..)