they're not
lets look at this from a few angles
first in a street car (which is what most of us are dealing with) :
in a street car you are not putting enough stress and flex to the structure of the car to benefit from the added bracing that would be supplied if these bars actually worked in the first place, most of them don't.... next for all of these bars to work as advertised you would need to have ALL of them... at that point it would be cheaper (and look less ridiculous) to put a full cage in the car... now we get back yo where we started on this... you are driving a street car... you are not going to put the car under the cornering forces that would require all this extra bracing... not to mention chances are you are running on street tires... and guess what even the best street tires out there will not hold the cornering forces required to make all of these bars worth half a shit
in a race car:
in a race car you will see cornering forces that make the added bracing a requirement... you will also be running on an R comp tire that can hold the cornering force... so what bars should you run now... none of them... you should have a full roll cage built to whatever spec the rules for the class you are running in allows...
pretty much all that any of these exotic bars do (and they do this VERY effectively)... is separate you from your money... and you are left there like the kid with the stock suspension 91 4 door accord who swears his car will out handle a lotus now because he has a front strut tower bar... its perceived handling.... just like the perceived horsepower ricers get when they add a fart cannon to their D15B7 and think they can go out and smoke mustangs and supras
now this doesnt mean all of these bars are 100% useless
after getting good suspension, be it shocks/struts and springs, slip on adjustable springs, or full blown adjustable coilovers... there is some good that can be achieved for a street car with some additional bracing
the biggest difference will be achieved with sway bars... the rear bar being the most effective... the front sway bar is there to tame the rear and keep the car from being too "tail happy"...
once that is done then a GOOD set of strut tower bars will make a small difference...
for the front:
as far as basic 2 point bars go the neuspeed connects at the best locations (at least on hondas with double wishbone suspension) they connect to the upper control arms.... then there are your more exotic models like the carbing and passwordjdm 3 point bars that connect both strut towers and the firewall... if the 3 point bars connected the upper control arms and the firewall they would be the shit... for cars with struts that dont have upper control arms, you want a bar that completely supports the entire top of the strut tower with the thickest and strongest material... then you want a bar that does not have hinges or pivot points at the mount locations... and make sure that the bar that connects between the strut towers is as stiff as possible... if the bar pivots or flexes, its not doing anything for you...
for the rear:
most of these will have very slight effect on the cars handling... although a hatchback will get a lot more from the bar than a coupe or sedan will... a car with fold down rear seats with a giant gaping hole between the rear seat and the trunk will get a little more than a car that has some bracing there from the factory... but the rear strut tower bars dont really have a HUGE effect on the car... and again the design of the bar comes into play
beyond that i havent seen many bars out there for a street car that will make much of a difference... and as i said already your tires will be more of a limiting factor than whether or not you have abcdefghijk___ pillar bars
