My wife and I have a 2008 Mazda 3 i sedan. Nothing fancy. Manual windows, manual door locks, super basic.
That being said, we love the car!
I'm looking for some ideas to freshen the car up cosmetically and make it feel "newer" handling wise. What I mean by that is that the suspension feels a bit "loose" in corners and over bumps.

 

New bushings, possibly new struts/shocks, and see if you can find a set of factory 17" alloy wheels in a bone yard or on one of the many online sites; that'll make the car drive very well.

 

Don't overlook the little stuff. I had a Mazda6 a while back that was getting tired and I was getting tired of it. I had it detailed and had the little problems fixed and it felt like a new car again. Simple things can make a huge difference. My sun visor was not locking in place. It didn't droop far so I did not bother with it. It just sat in front of me as an imperfection in my face every time I drove it. It was a $5.00 part. It was worth it.

What are the things that you can do that would make the biggest impact for the investment. I like to buy new floor mats when they start to look bad - after 4 years or so. While not cheap. It is a heck of a lot cheaper than a car payment.

If it is too much to go for a detailing. Do it yourself. Spend a Saturday cleaning it from top to bottom. Get everything you can. tires, wheels, windows, seats, carpet, door jams, everything that can be cleaned. This week I tried something different. I washed my oldest car three times with a wash/wax combination. The first time I used a standard mix of water to soap combination and did a through job. I dumped the water and mixed a lot of wash/wax and a little soap and washed it thoroughly twice. I even sprayed with a mist to let it soak in for as long as possible. The car looked new when I was done.