Strut bars can help tighten up an older car with lots of miles (reduces chassis flex). They also help cars that are driven "very hard" (rally, rallycross, autocross, track, etc.) On a newer car that is primarily driven on the street the difference won't be much.
My FS rear bar seems to tighten things up pretty well, but i tend to take corners a lot harder than i should....but i probably wouldnt notice it if i drove like all my friends, about 2mph around ALL curves/corners/anything that isnt a straight line. worth it to me, maybe not to others, depends on how you use your car [dunno]
I got the Massive front bar. The difference wasn't the world by any means, but it made the initial turn response a little crispier, especially at higher speeds. I don't think it was a bad little $100 mod.
'Sides, they always make your engine bay look cooler. =)
IMO I think the read onw does something for handeling but thefront I think is just for looks. I put my rear FS bar on first did a lap arround the block noticed a fairly marginal (what ever that means) diff. then I put on my front and couldn't tell of any perfor. gain...but like stated above it does look sporty in the engine bay so I left it.
I have both but simple geometry and statics tells me they don’t do anything to significantly stiffen the chasse, with out anything tying the bars (font and rear) to the body in a third point i.e. making a triangular connections there is no way for the bars to transfer any significant load. But they make real nice places to use as tie downs and to lean one when working on the car.