Look for things that must be done, and use that as an opportunity to upgrade.
For example, wear the tires you already have out, and upgrade tires at that time. Or if you want tires now, look for some used tires, like take offs, that you can buy reasonably priced. Go with cash and plan to bargain, as many folks ask way too much for used stuff, but they get realistic when they you know have the green in hand.
I put safety as a top priority. I installed a Rock-Hard cage system. You can buy the parts you need and want, and install them yourself without welding. They take advantage of the factory cage, and with DIY installation, are less expensive than a custom cage (notice I did not say cheap, as you can easily get into $500-$600 bucks).
A High Capacity forever type air filter is a fast and easy change, and again, makes most sense when you need to change your existing filter.
IMO, unless you do major engine upgrades, I would not spring for a new intake as they are expensive and even the manufacturers charts show the HP gain is at pretty high RPM (levels you may never rev to in practice). So you get a lot of the benefit simply by installing the High Capacity air filter.
