I only agree with the range and cost increase , but the damage increase doesn't feel justified.
T3 AA sams are already dirt-cheap for the amount of DPS they provide , along with their tanky health.
A range and cost increase will serve greatly to make them less DPS effective early T3 stage against T3 gunships (which i believe they shouldn't be effective against at all, just like how T3 Land defense isn't as effective against T3 heavy units , unlike how T2 defs compare to T2 units)
For the argument to hold , compare the percy (7200 HP , 1280 mass cost, 337 dps, 34 range) against T3 uef defense (6500 HP , 2000 mass , 272 dps, 70 range) and the SAM(7000 HP , 800 mass , 342 DPS, 60 range) against T3 Uef gunships (6000 health , 1500 mass, 250 dps , 44 range)
Land gameplay is highly dependant on range since land units are far more slower paced , thus the turrets doubled range is justified, along with its mass cost.
For air however .. the units are far more mobile , the range difference between SAMS and T3 gunships is 16 , which is fast to close by air units . The main point of T3 sams should be to provide a stationary defense for a large area against weak/harrasing forces , not to completly block tactical avenues for the enemy once they are spammed enough(which is very convenient to do because of how cheap they are for their utility)