What are some inexpensive upgrades for my suv?

[KtaoKid]

I'm getting a 2000 Mercury Mountaineer for my first car, and I want to know of some cheap upgrades I could do. Things I was thinking of is a new muffler (sound) and i heard that a high performance air filter will add more horsepower. I mainly want small minor but useful upgrades to make it a little better. Any other ideas are welcomed. Things like seat covers, floor mats, a new sound system, or maybe even rims are good things to mention also. If you could, could you also add links. That'll be helpful
Thanks

 

[Mark]

Typical K&N-esque cold air intakes are scams. They advertise an addition of 5 to 10 horsepower, but thats at 5,500 rpm (or wherever peak is on your engine), so if you have a 200 hp engine thats a gain of 2.5% to 5%, and thats assuming you actually gain hp. A stock intake system pulls air from the grill, near the headlight housing. Nice, cool air. A cone style cold air intake takes air from the middle of the engine bay, near the exhauat manifold usually.... Shitty hot air.

Put a flowmaster super 44 on it, other than that, i wouldnt touch the motor. It will never be an exceptionally fast vehicle.