Given time the GTVA would reverse engenier every single shivan tech and then improve it. Well they would need not only time but something to work on as well. And considering how fast they managed to reverse engenier those mara's i believe that within 2 maibe 3 years they would reverse engenier almost every shivan tech ! Sure there would lots of money and research done but hell it would be worth while.
Man just imagine if they got they hands even on a small cruiser like a Lilith or a corvette....man oh man....! The really sweet hing would be if they got theyr hands on a Ravana. Now that would be something worth getting excited about. Just imagine better beams better armour better subspace tech better fighters better ships (well when taking into acount all the + and - shivan warships and GTVa warships have the GTVA has the better ships, or rather ship designs that is!)