What Hotchkis offers that the others don't is a relocated upper control arm forward mounting point...., It completely changes the geometry, according to them it corrects excessive caster gain, creates the proper negative camber curve & reduces bump steer... All I can say for sure is it completely changes the handling of these cars.... Do you need to do it? No... The other control arms offer some of the benefit.... But if your serious about going around corners I think it's a worthwhile investment....
Oh, and if you would prefer to keep $$$ in your pocket just do the Moog offset bushings in the stock control arms.... 75% of the improvement for 10% of the initial cost & keep in mind if you spring for the Hotchkis stuff your alignment is gonna take extra time & time = money... Plus the helm joints are prone to wearing out quickly...
FWIW I invested in good shocks, big sway bars, offset bushings & a performance alignment.... I when for a mountain drive with a few friends with Porsches, obviously I didn't outrun them, but I did get a few comments about how surprised they were I was able to hang with them....
