Originally I used 4x4 rear flanges and Sierra 4x4 cos discs and on the front I stuck with the std Sierra legs and hubs with the granny calipers and 2wd cos discs. It all fitted with a very slight fettle to the front carriers. Subframes are identical but its easy to leave the complete engine and steering system connected to make easier when swapping. Imo mine understeered no worse than a std 2wd cos but recently I changed from the 29mm Granny arb to a 2wd saff version and its made a big difference. I think the weight of the engine is always going to make it understeer if you don't get the suspension right.