I'm thinking about buying a complete set up, front and rear strut bars, pillar bar, 4 point sub frame, rear side brace, and front lower tie brace.

I'm doing this for the health of my car (reading that the car flexes and bends) and the benefits of the handling.

Would purchasing these be worth it for those reasons?

 

Honestly, the gain of each would be extremely limited. First and foremost to increase handling capabilites I would look at tires. If that is already covered and you don't want to or have already addressed suspension, I would start off looking at something like a trunk cage. Even they seem to provide pretty minimal gains, but would be better than a lot of the things you have listed. I personally, have never felt a strut bar that made a difference. This is from an eBay bar to Cusco installed on Honda, Toyota, Camaro, etc.

 

unless you drive your car like a maniac through twists and bends, then there are no point in you buying all those parts.

Strut bars, under brace, etc are all meant for race (or used like a race) car. They make the frame more rigid so that handling of the car feels more 'tight', it will be more responsive in every way... not just talking about your steering wheel, but also will be more sensitive to uneven road, bumps, potholes, etc.. it does not significantly add anything for the straight smooth road though, it will only be noticeable when you're going fast through twists and bends...

so agree with the above posts, if you're daily driving your car, your best bang for the buck would be lighter wheels and decent tyres.

 

And if you do get strut bars, stay away from single bolt and nut designs on each end. They are worthless and more for show than function.