I have an 84 trans am and I want to improve the handling by upgrading the shocks and springs. What should I upgrade it with. Also I want to drive this over 100 miles in the interstate. What would I be able to do to meet that goal.

 

Upgrade to poly bushings, install a Wonderbar...

 

The '84 Trans Am already has great handling springs and sway-bars. Replace the struts & shocks, and any worn-out bushings. Wonderbar is a good idea.
Use polyurethane for the sway-bars, and stock rubber for everything else. The best struts are Koni, however they are expensive.
I put some new KYB shocks on the rear of my '83. If you want to lower the car, there are people here who can reccomend springs for that...

 

To me you cant beat Eibach Pro Kit springsl the way around. They do drop the car by 1inch and I really like that. Also makes the car handle much better. And, you cant beat subframe connectors.

 

This definitely.

And this is HUGE!

 

With polyurethane bushings, it'll ride like a buckboard, and there will be more road noise. Use poly only on the sway-bars...

 

I agree!!

 

FWIW comments & opinion based on almost 700,000 miles of driving half a dozen 3rd & 4th Gens with various suspension set ups over ~35 years.

With crappy to mediocre springs, struts & shocks subframe connectors seem to help or camouflage the weaknesses of the mediocre parts.

If the springs, shocks, struts & sway bar are right subframe connectors don't make much if any difference in handling in my experience.

As for preventing rattles, squeaks and keeping a car tight, subframes connectors are worthless.

​My 91 RS was just as rattle free and tight bodywise at 389,500 miles without subframe connectors as it was new. The rattles that existed were t-top rattles from bad weather stripping

My 99 T/A had subframe connectors from ~7,000 miles up to the current 169,000 miles. My 02 Z28 has 254,000 miles and no subframe connectors and is just as tight and rattle free bodywise as the much lower mile 99 T/A.

Drag racing subframes connectors help.

Subframe connectors that can be used as a jacking rail are useful.

Eibach springs look nice Over time they tend to sag a little. That's been true on my RS & TA.

Bilsteins all around are excellent on both 3rd & 4th Gens. My RS, T/A , Vette & Tundra all have Bilsteins. Excellent quality no issues over many miles. There are other superior choices but Bilstein performance, quality & value is a very hard combination to beat.

For the money KYB's are decent enough and I've made do with them several times. Sort of my idea of minimum acceptable shock or strut. However all of my KYB's were toast by ~60,000 miles. Have had Bilsteins go ~120,000 miles.

Humor...(Back in the day, a manager at NAPA became upset with me for ordering German Bilsteins for my American Camaro. "I've never heard of putting their parts on our cars.. Don't put that stuff (Bilstein & Bosche parts) on an American car! Buy one of their cars if you want a German car!" - No joking )