Only thing I ever spent 1k on was a windshield, and boy did that suck. It was the last new windsheild available in the country
so it's bronze, and doesn't match all the other blue windows.
As far as mods go, all of mine suck. I still maintain my car was much faster before I started screwing with it. The stage 1v4 is nice, but without power going to my rear tires (for whatever reason my AWD isn't working) I can't really utilize it. My fronts just spin all day. 1v5 is out or coming out and should be better so if you want cheap "gofast" I'd get that.
If everything works, good good wheels and tires are hands down the second best ting you can get. I wanna say the Konis are on top but I have never felt them. I can only imagine having better handling in this car. It would be really sweet.
If not everything works, fix it, unless it's the transmission or AWD system, then replace it with as you say something better. My tranny was rebuilt for $2500 after it broke but apparently that didn't include powering my rear wheels so, I intend to do an MT swap sometime down the line. I won't waste money making my AWD work before then.
ECUTune + koni/springs + sweet tires = aweSomeVX