Eh, I started with visuals on my overhaul... Full interior and exterior re-do. Paint job was about $2000, rims and tires were $1100, body kit fiasco has cost me just $430 so far, but we'll see how that goes... Interior vinyl and padding was about $100, seats and 5-point harnesses were $300 total, prolly about $100 on paint and liquid vinyl stuff for the interior...
So that's about $4k total on looks, $0 on performance.
Not a single engine mod yet other than $30 for my infamous PVC WAI.
It's all about what you want, really. I do plan to do engine mods, but the body of my Alero was pretty jacked when I got it and it was that light blue color you see fags driving with rainbow stickers on the trunk lid all the time lol. I just want a hot looking car for the moment, since this is going to go to my son someday anyway and I want him to be old enough to remember a bit about the process of doing all the mods (He's about 6 right now).
Good luck,
-Brad