shopy

hello every one im new here and i like to ask for help on choosing the right configuration of lexia 3 and diagbox to buy for my c5 2009 gasoline. i see many on alibaba and i see some on ebay .but to choose to buy the right one that will help me diagnose my car and other cars in the future is hard for me.can some one help on this ?? do i need the last diagbox like 7.76 and lexia 3 ver c with A 1281 Z or i can use the 921815 c with one of the diagbox that are there on china market. thanks