I find the search radar to be perfectly adequate until you bring it into an uptier where attack drones start showing up, and if the Radar is insufficient, you can always to 1/2 full sweeps with the IRST, which usually picks up what the radar misses
if you mean at minimum altitude, theres a bug report for it to get 2x M2 .50’s attached to the launchers so you can aim it, (Community Bug Reporting System)
the Damage is a lot better than it used to, but its the classic Gaijin buggery i mean just compare these two
Why such a difference in damage?

(on 2S38)

the damage comparison between these two isn’t even close, and the 2S38 has around 1/3rd the explosive mass, and 1.5x the radius, meaning it should do less damage, but it does more
I manage a 3.45/1 K/D against air in the rapier, (100 air kills, 29 total deaths) and i’d wager 80% of my deaths are to ground vehicles, so it’d be much higher against air alone,
It is annoying, and there is a bug report on it (Community Bug Reporting System), it can fire over the front, but you need to meet the guidance area of the missile in 3rd person before moving the mouse back down to aim at an aircraft,
aiming at a target over the front is possible, but your minimum range is much larger than any other aspect
Personally i find it to be a functional SPAA, and one thats quite good used properly, but it’s not ideal, and personally i’d take the SAD or HVM over it, any day, my main issue with it is the lack of damage, but the missiles are fast enough and pull hard enough to get multiple hits quickly with it, and can even be used to intercept munitions if you have the eye for it, once it gets its damage rectified further, and its firing arc and .50s added, it’d be a great SPAA, on par with the Osa, and ASRAD, or Rolands at a basic Minimum