What are things to consider when making an effort to improve your cars handling?

I have a 2003 Honda Element awd and before that used to have a 2006 Mazda 3i that had pretty good handling for what it is that it had no problem handling highway curves at triple digit speeds(110 mph). My truck on the other hand taking those same curves on the same EXACT allocation I'm only able to get 85-90 mph out of it before things get ugly!

I know my car is not a sports car but is there any possible way I can bring my trucks handling up to the Mazda 3s level? What parts can I focus on? Tires? Suspension(KYB?) ? Sway bars? Polyurethane bushings?

What you should consider, Mark, is that you've got a car that's only worth about $2,300 dollars and because it's a brick on wheels, there are inherent limitations on making into a high performance vehicle. You've already dumped thousands of dollars into upgrades and this isn't increasing the value of your old beater.

I have a quick question. Just give me a few min to post it

You will never get an SUV to handle like a car. The laws of physics are very clear on this.

You are dealing with momentum, friction and centrifugal forces.
You ain't going to win

With all the money you've spent trying to make this car into something it wasn't DESIGNED to be, you could have bought a sports car, or a sporty sedan. What's next, trying to swap in a V8 engine?

Tires. Brand name radial tires. Also stop comparing apples and oranges. Forget the car you had. This is your new limitation. Like it or leave it.