I just plain don't get it, you say you need to make a choice for a pattern starter plane between one that is 10 oz heavier than other, the other has some paint chipping problem, or a third, for which you can only source the fuselage???? Jeez, that is though decision...what are you exactly expecting people to tell?

Being in Argentina, why don't you call Mr. Columbo and ask him if he can sell you their new Pattern plane, designed by some obscure French pilot who only won the Worlds a coupe of times. Rumor has it they call the plane the"Osmosys", the new offspring of the Synergy / Oxalys family that they have been developing in deep secrecy for the F3A Worlds in Argentina. It should be a fantastic F3A starter plane, lighter than the Infinity you mention, better painted than the Genesis (well it's from the same factory, who knows?), and you can even get the proper wings with it!!! If you track Mr. Columba down, ask him if Mr. Taboas has finished the three planes for Christophe...

Sorry for being too ironic, but I couldn't help myself...

In any case, get a plane you (and your wallet) are confortable with...