It's harder for the engine to turn a taller tire with a given gear ratio. The final gear ratio is what gives the engine leverage to turn the wheels. The 4.30 ratio needs to be changed to 4.70, with 35" tires, to give the same mechanical leverage the 4.30 ratio had with stock 32" tires. Even if you could change to a 4.70 ratio, that wouldn't compensate for the extra weight of 20" wheels, the heavier 35" tires and the extra weight of the 6" lift components. With the taller tires and all that extra weight you may need something like a 5.30 (?) ratio to get back to the same mechanical performance as stock.
